has a good synth engine (although you need to be careful, switching tracks can result in losing your edits very easily). Also the pads are fantastic, they have aftertouch as well as velocity and are an absolute joy to play on.
On the negative side it's an incredible pain trying to edit everything through a 2-line LCD, and although you can do x0x-style grid editing it is on the same keys as the patch editoing categories (Filters, LFOs, etc. ) so you have to switch out of sequencer mode constantly to edit the sound. I thought I would enjoy sequencing it with the Octatrack, because I liked the Emu sound/architecture in general, apart from the FX routing. To my surprise and disappointment, I hated it (except for the pads) and sold it within 3 months. If you want Emu sounds I advise to buy a rack. Although I still miss the pads.
The RM1x has a much simpler and inferior sound engine, although the onboard effects are quite good. The internal samples are 'good enough' especially for bread-and-butter drum tracks - a little swirl, distortion, and reverb and you could have something quite usable. I love
the sequencer - although it has some limitations (like you have to stop the sequencer to change tracks in grid mode; they way around this is to program all your drums on one track and then use the wonderfully-named 'track explode' function to automatically spread them across a bunch of different tracks). The sequencer is very quick to work with in real time and would pair well with your Octatrack.
The #1 thing it does (also on the RS7000) is that you can pull parts from different patterns. Imagine that you have some 500 or something preset patterns and maybe 50 of your own patterns in different musical styles. So each pattern might be 2 or 32 bars long - much like any other sequencer. So...say you made some 4-on-the-floor beat that's 8 bars long, but you don't like your hi-hats. Then you remember that pattern XXX has a great hi-hat pattern, but it's only 4 bars long; no problem, you can just drop just the channel with the hi-hats into your own pattern, and it will loop automatically. You could also add the snare channel from pattern YYY. So you can treat the patterns like construction kits and just take different things from different patterns to build up your own very quickly, and of course all the BPM matching etc. is automatic because it's MIDI. Likewise you can easily switch drumkits per track.
This is really fantastic, and especially for drums, because you can take a loose funky snare thing from one of the hip-hop patterns, grab some disco-sounding hi-hats or percussion from somewhere else and just mix and match freely. Change the kit on each track to get the basic sound you want, tune it a bit, put on some gentle effects and boom. When I had one I used this often because the programming on the internal patterns is really excellent; it's super-easy to put in your own ideas but there will be times that it would be wise to use existing patterns for some instrument that you could not play on your own.
The MIDI effects (delay, octave etc. are also quite useful, and the 'groove' editing, which is sort of like swing on steroids, is also great. Switching between patterns is very easy and it's also easy to convert patterns to songs. Editing the list of MIDI notes etc. is very straightforward; it gets tedious if you are dealing with a lot of CC data but if you just want to edit the notes you can filter CC, pitch-bend etc. out of the display.
As you can see I have a very high opinion of the device. I frequently think about buying another one to run alongside the OT and A4
and I think you'd enjoy it a lot since you have a similar setup. The only area where I consider the sequencer weak is that it has a very basic arpeggiator, compared to something like a Roland MC-80 where you can mix a 30-40 musical motifs (note patterns) with 60-70 different rhythms which is the ultimate in flexibility. But since you have an OT and the arpeggiator in that is super-programmable and can be p-locked, that's not going to be a problem for you.
For you I think the RM1x would be a particularly good combination. Unless you want to go large and buy my RS7000
that I'm not using