i would advise against buying it. this is the one thing i would say that they need to improve upon. like you, i was going to buy that same unit, but decided on the hydrohut instead. three reasons: 1, there is an actual double floor, not a velcro deal like the one they sell. 2, there are many more venting options than the htg model has and 3, the frame is constructed out of steel instead of plastic. this doesn't sound like much of a big deal, but when you've got lights and fans hanging from your shit, you'll know why you spent the extra money.
Hydrohut Mini 39" X 39" x 6.5' NEW IN-BOX - (eBay item 200076860178 end time Oct-04-07 12:34:03 PDT)
that's where i got mine and i'm happy with it thus far. be advised there is no stealth shipping for this thing, as it comes in the manufacturer's box, so make whatever arrangements you need. i don't regret spending a little extra money on my hut, because you get what you pay for with these things