Well, the R5k remote extender was my first time working with any of this JP1 craziness. The extender was brand new, and beta at the time. But very stable, and worked great. It took a good couple days just to understand the flow of control, but once you get your first code to work, you're hooked. And the fast macros alone make these extenders absolutely amazing, but they go WAY beyond that. Fast macros, by the way, are just that. FAST. A normal universal remote will take a few seconds to do a 3 or 4 step command. The fast macros do it in literally less than a second. It makes a HUGE difference in usability.
I think the hardest part to figure out was the interconnection between getting the codes, putting them in KM, and then into IR. It's three or so programs that need to work together, and it takes a bit to understand what parts need what information, as KM can do a LOT more than we need it to. I think the most important thing to know is that all you really want to use KM for is specifying the kind of remote, the code number, the code type (sony, etc) and then entering in all the codes (for each command). That's really all that should need to be done. You could move around some keys a bit, but other than that, the macros, and keymoves, and everything else will be done in IR. At least for the r5k remote. The macros are done there, as are the device specific macros. But again, all of this just takes some getting used to. You really just have to sit down for an afternoon with the remote hooked up, and the software running. Play around and try and get it working. It's really not THAT hard, it's just quite a lot of confusing things thrown at you at once. Sort of comparative to just suddenly deciding to jump into using linux. It's just a whole lot of basic stuff to get figured out, and then it all makes sense. I can't stress enough how much it's worth it.
And I really like the r5k remote. I am interested in trying out the 2116 remote, but I guess in the quest for simplicity for the most used portion of my system (the replay) I figured I'd use the remote that was built for it. The preset locations of all the quickskip and replay buttons are pretty awesome. So I just keep them. Plus it's family friendly for the basics. It's one button to turn on the whole system and set it up to run the replay. And then the remote acts naturally (except I removed the display button, as pressing "select" always does the same thing, and then I could place a universal macro on that button to change my TV's display mode) Of course the replay and TV buttons act a bit different, but much preferably, I feel. Can't beat it!
Hal's written a kick ass extender, and I couldn't think of anything that I would want it to do that it cannot already do. It's that feature complete. An endlessly reconfigurable universal remote for $20 for a cable and a lazy weekend worth of time seems like a damn good deal to me.