I agree with Smulkin. I like to be able to see at least some of what's going on in there. If you want to go with a tub, I recommend reptiletubs.com. They have a 4.5' monster tub that is only $35 (don't know what shipping is, I got mine at a reptile show)

I use it for my 7' 4" 21 lb dumerils boa.