It's going well. I'm playing through it with my girlfriend and we're on chapter 2. Occasionally we run into a monster that has a non-default ondeath script. This is pretty rare, though, and when it happens I just award xp manually. It'd be more work than it's worth to include fixes for that.
I haven't done much testing for ECL and the version of pwfxp I used as a starter I believe was based on PRC 2.2, so not all races are included anyway. Because of this (and because I never really agreed with ECL as a way to balance races) the version I'm working with has ecl xp penalty disabled. It'd be easy to add it back in...the code is all there. I'd just have to add all the newer races.
I'm also running it with a 40% party bonus. This equates to a party of two receiving ~70% of what a single player would get. That's easily adjustable in the .nss file, though. That's considerably higher than the default, but I felt 70% was more appropriate than 60%.
Otherwise, yeah. It seems to be running perfectly. Getting the same XP rewards that I would have if I was running normal bioware. This means that any module that's been playtested with the bioware xp system in mind should run at exactly the same pace with this system. No leveling too fast or leveling too slow problems. If for some reason the module has the slider set to something other than 10, I recycled PWFXP_GLOBAL_MODIFIER (off the top of my head, might be wrong) to function the exact same way. Set to 10 = same as bioware slider set to 10.
If you want to run with the above settings installation is simple. Just import the .erf, turn bioware xp off, and go. I'd be able to walk you through any personal customizations you'd like to make.
Summon/henchman/dominated/etc xp penalties are, of course, off by default.