Hello there!
I think HT's Colonial Marines are great figures. I own Hicks, Apone, Hudson, Drake and Ripley, and have the PL on pre-order.
I don't own any EVA kits, so I can't give you any comparisons, but here are my thoughts on the HT figures.
First off, they're pretty much kits, i.e. you have to put them together yourself, the first series you even have to put the torso/head/arms together!
All the gear and clothing you also have to put on yourself.
They are very detailed and mostly very accurate, you just have to leave a few things off and do a couple of repaints and headsculpt switches and you'll have a bunch of awesome looking marines.
If you repaint Apone, Ripley and Drake you'll see the likeness is not that bad (Apone's goatee and sideburns, and Drake's moustache and sideburns are just painted on). And if you repaint Hudson, you'll find out he looks much more like Hicks!
The uniforms just need a bit of weathering and they'll look much better.
The weapons and gear are all top notch, especially the pulse rifles and armour, those things are unbelievable!
For pics you can head to the sideshow freaks forums, look for the aliens thread, there's lot so of pics there.
My Aliens & WWII site:
Aliens meet WWII