My humble advice: Get the OT if you think you will have the time to spend on it.
Yes, you can lay down a 64 step pattern with 8 tracks and fuck around with the
p-locks until you get something you're satisfied with, but that can take months to master, or maybe a couple of hours

Then you'll find yourself stuck with patterns and you may jump into
Scenes to add more variety to your jam, but that will become boring soon too, so you will discover
Parts are actually useful, then again it will become boring, that's when you discover how powerful the
Arranger can be to get a proper song.
Once you're done with it, you will want to go back to few steps pattern again, this time with one-shot samples, maybe tracks with different length for Steve Reich and concrete music.
So it is complex, it can do fake self generative patches out of hiss noise, drum machine, frippertronics looping for your guitar, etc.
And again, for something like techno, seems to be a very capable machine once you get the a proper collection of samples.
Actually I made my decision on getting it after knowing it's the center piece of The Field, and I'm not really into "techno" lol
(skip to 3:50)
[youtube]http://www.youtube.com/watch?v=TwXcarHyr1U[/youtube]
Octatrack Manual is the only tab I haven't closed in my browser for about a year, most of the time the answer is there, so a simple ctrl+f will do the job.
But there are a few guys on YouTube doing great guides/tricks for all levels, Cuckoo has some good stuff if you can stand ~40 min videos, and max marco is nuts, don't open any of his videos until you have spent months with the OT (but seriously, he has opened this machine way beyond Elektron ever probably ever intended, like routing MIDI IN to MIDI OUT for conditional sampling? WTF

).