HP Envy

I say first one if i had to decide between that and the HP

I have this model of ASUS http://www.ebay.com/itm/ASUS-G73JH-A2-Laptop-17-3in-FHD-8GB-1TB-Win7-64bit-Intel-i7-720QM-ATI-5870-Video-/231153267928
And i've had it for over 4 years without needing to upgrade anything at all. And even if I need to, I can because this laptop is open friendly. ( Meaning you can take it apart and get it back together with basic assembling )
My only comment on taking it apart to add would be the screen will not turn on for you if you have something off-set inside of the laptop when putting it back together, and or if something gets off-set from an impact, assuming you didn't break the screen lol.

Idk, I've had good luck with Asus, I've had HP desktops but they are very old models and not good for me to give references on due to being out of date.

Not a fan of the life span of most laptops, but of those two the HP for sure, just because of the significant CPU difference. The HP has a quad core i7 chip which is quite a bit more powerful then the Asus i5.

I'd go with the ASUS Notebook. :3

The Asus is better.

HP: Better for office, media and art stuff, fast CPU. Shitty for games, though.

Asus: Good for games, but slower CPU. Still good enough for most office and art things, though.

Go with the ASUS

The HP, for $20 more you get a faster CPU and a touchscreen, though the Asus has an nVidia graphics card and the HP has Intel graphics. nVidia is better than Intel as far as graphics go.

Asus has a good reputation for build quality whereas HP does not. Not that HP is bad but Asus is a well respected brand. I have a ten year old Asus motherboard that works great (old as hell though), and a three year old netbook that also works just fine. YMMV as always.

I'd recommend the Asus, unless you do a lot of work in Photoshop or similar programs that require a lot of CPU.

ASUS, no contest. HP is really really bad.