But I will probably need to sell my Montage to buy the 88.

Whatever path you choose be sure to save your user data from the Montage AND TEST those saved files before you get rid of the Montage.

Keep in mind that a Modx/Modx+ can NOT load a BACKUP file produced on a montage. So don't use that file type to save your data.

The keybeds are different and will have a different feel to them. Whether that is an issue for you only you can tell.

Another major difference is the audio system. This is from the Montage Owner doc

The MONTAGE features a built-in 6-channel in/32-
channel out USB audio interface for recording the high-
quality sound of the MONTAGE on a Mac or Windows
PC—without the need for a separate device! The
MONTAGE also supports high-resolution 192 kHz audio,
making the ideal keyboard to take into professional-level
recording situations as well. The connections are also
compatible with iOS devices

Notice the difference between the above and this from the Modx+ doc

The MODX+ features a built-in 4-channel in/10-channel
out USB audio interface for recording the high-quality
sound of the MODX+ (at 44.1 kHz sampling frequency)
on a Mac or Windows PC—without the need for a
separate device! The connections are also compatible
with iOS devices.

6 in 32 out versus only 4 in 10 out. Again, only you know if that is an issue.

Same with the 192 khz versus 44.1 khz.

Same if you use/need Seamless Sound Switching. The montage supports it for performances with up to 8 parts. The Modx/Modx+ only supports it for up to 4 parts.

I might discover I don't like programming on the MODX's touchscreen and will have to deal with that

There will be little difference in programming/using the touchscreen.

Maybe find a MODX in a shop and spend 10 mins programming a patch to see if the touchscreen-only UI suits you.

I have a MODX6 and I've been thinking for quite a while to get a Montage, since, even on the MODX, I use the available buttons (cursor for example) quite a bit.
The select buttons on the right + 8 sliders for FMX are really tempting, as is the audio interface in the Montage. (If you use the keyboard in the studio, the 44.1 KHz interface of the MODX will be a huge downgrade).

Do you need the increased FMX polyphony of the MODX+? I guess you can find a second hand MODX (non +) at a pretty low price and maybe you won't need to sell the Montage.

[quotePost id=123305]the portability and decent action of the MODX8+ has my eye right now.
I welcome anyone's input who has experience to know the pros and cons of both the Montage and MODX lines. Will I be disappointed with the 8+ after playing an ES and a Montage all these years?[/quotePost]
This is somewhat subjective, but from my experience I absolutely HATED the GHS graduated action keybed on the MODX8. When researching for a new Synth 5 years ago I was eyeing the MODX8, Montage 8 and Kronos 88
I was first able to demo the MODX8 at the music store and I left there so frustrated & disappointed because the pianos were virtually unplayable for me. Pianos was my #1 most important criteria. I found that the pianos played awesome on the highest two octaves, but as I went down to near the mid way point and below, I had to increasingly smash the keys harder and harder with a sledge hammer to get them trigger the velocities properly as I went down the keybed toward the lower notes. Once I found the Global Velocity setting and set it to trigger velocities more easily, the lower & lower-mid keys were much better, but past the mid point and most especially the highest two octaves were way too hot and likely were hitting 127 velocity with just regular medium playing. A month later I tried the Montage 8 (BHE keybed) and it was so good for playing pianos (perfectly balanced and even across the board) that I paid double the amount of the MODX8 for a synth that was twice the weight...

Here is a video that you can get a sense that there's something not right with the MODX8:
https://www.youtube.com/watch?v=8ob4o2xEH6Y

And both keyboard are at the same volumes, because you can hear that they are on the higher notes at the 0:22 mark. If anything the higher notes on the MODX8 sound slightly louder than the Montage8 until he gets down to the high-mid C5 note. At 0:29 he is playing the same velocity on both, but it sounds like he's playing lighter on the MODX8 (he's not)...

So, I would only caution you that if pianos are important to you and you play songs where the pianos need to trigger at the proper higher velocities in the lower ranges, then you might want to rethink the MODX8+

However, as a workaround, you could have your pianos saved as custom Performances (not use the Presets), split the lower to upper middle range up into 2 or 3 sections (each with different PARTs) and change the Dynamic Velocity of those PARTs, adjusting them so that they trigger those ranges better! For playing live gigs, I would actually probably be ok with that, basically using 3-4 PARTs for a single PART piano... The problem for me would be that I generally use all 8 PARTs in most songs and wouldn't have enough free for the extra piano PARTs. I would get a MODX7+ if it were for live gigs!

If you don't care that much for pianos and only play them softly anyway, and you care more about other sounds, then this might not be an issue for you and the MODX8+ might work fine! But that is all just my personal opinion and experience with the MODX8 vs the Montage8

Lost things on MODX+ vs Montage
1) Navigation buttons in right hand side as you've mentioned
2) Aftertouch
3) Ribbon Controller
4) SSS (seamless sound switching) only works for 4 or less Parts - not 8 or less as with Montage
5) No assignable outputs (Montage has assign outs - which, although slightly limited (no master/system FX), offer more output choices)
6) Lose 6 stereo channels of USB outputs (MODX+ has 10, Montage has 16)
7) Some missing options on the knobs above the slider. Only 4 so not all parameters for fixed-function knobs are available.
8) Although the knobs and sliders can be banked (switched) there are still only 4 available at a time
9) Visual indicators for current position of knobs (Montage has LEDs around them, MODX+ doesn't)
10) Can't load your Montage backups (neither MODX(+) nor Montage can load the other keyboard's backup file .X?A). Library and user files are compatible.

Gained things in MODX+ vs Montage
1) USB level knob in MODX(+) not available in Montage
2) Touchscreen shows knob position and there are other touchscreen differences which compensate for #9 and #1 in the previous list.
3) MODX(+) is lighter. Sounds like a "loss", but it's a gain in my book.

Subjective differences
1) Keybed (discussed by others)
2) Construction (more plastic - less weight - but some prefer more metal as in Montage)
3) DAC or analog audio path. For MODX (not plus) I've seen complaints about the levels of MODX. MODX+ has different DAC than MODX so this may be "better" now. I haven't heard any reports on this as of yet. For now, I'll just put it here.

These are all very helpful responses. I will definitely go to a shop to test the MODX8+ for both the keyboard response with piano sounds (extremely important and relevant to my needs) as well as what it's like navigating the GUI without the plentiful buttons and 8 faders of the Montage.

I'm basically looking for an all-in-one keyboard that has the Yamaha libraries of sounds, is as programmable and tweakable as my Montage6 and Motif ES7, but has 88-keys and won't throw out my back. I've tried out (and read too many disappointing or mixed reviews of) the other options like the YC, CP, CK boards, but I fear they won't offer me the level of tailoring I'm used to with these workstations.

I always seem to end up considering getting a more vanilla feature digital piano like the P series and triggering other sounds via MIDI. I just want to be done hauling so much extra gear!

It's help, thx alot 😀
capybara clicker