I tried this out with the mod the other day and it's a definite improvement. The aliens are now very fast and deadly. They actually climb on ceilings and walls now too. I tried the Hadley's Hope level and get getting killed over and over again. Methinks co-op should be decent now - and you really have to keep your wits about you. If you don't, it's adios machachos. Aliens were even flanking me.
Graphically it looks pretty much how I remember it. Bear in mind Gearbox did release a 4gb texture patch for the PC version anyway, so it looks decent enough. The added effects the mod gives you are a serious FPS hit though. I wouldn't recommend going any higher than "Medium" unless you want a slideshow.
So, anyway, it hold promise.