Depending on which tank I'm lending out, I use either an older Dye 70/4500 (not peanut) or my DXS 48/4500. I use one of Deadly Wind's on/off's and the reg on my dye fits underneath the rail, so I can set 'em both up like
*Christ Krew**Death Before Dishonor*
I got a 45/4500 Crossfire a few years ago. To say the least, I don't plan on getting another tank. It just feels solid and has never given me any reason to doubt it. And if there is anything I want to be solid on my marker, it's in 4500 psi tank that is sitting 6 inches away from my head and heart lol.