I have an older SQ Balance, with the old style velcro latching integrated weight pockets. I purchased it back in '98 and have enjoyed it very much. My buddies gave me a lot of crap about buying that instead of a more expensive Zeagle Ranger. It is very, very comfortable to dive with, even with no protection suit and I've used it for both California (cold for me) and tropical (warm) diving. However, before I purchased my BC, I was first counseled by my buddies (1 instructor and 3 dive masters) to get my own reg. and computer. They said to get a good one and take care of it. You can rent BC's, wet suits, tanks and weight belts, but you want to have your own Reg that you know, service and trust. Just a recommendation I will pass on.
Now, if I had it to do over again..... As much as I like my SQ Balance, (aside from the velcro integrated weight system) I would look more closely at one of the interchangeable BP/W systems. I was looking at the Dive Rite's trans pac earlier today in fact. When I dove in the bahamas, being in just a 3/2 mil wet suit, I didn't need much weight or as big a BC bladder as I had. When I dive in California, I am maxed out for places to put weights in my integrated system and wished I had a steel tank instead of an AL80 so I could offload 10 lbs or so.
Having your instructor / shop owner pushing a 5 year old "new" SQ Balance isn't a bad thing as long as he is giving you a whale of a deal. If he isn't, I wouldn't even consider it. Don't be shortsighted and get something that will get you by for now but inadequate in the future. :no
I don't dive nearly as often as most of the people that chat on this board, but I know my equipment really well and know how to set it up and trust that it will work.
Whatever you get, make sure that it is comfortable for the type of diving you want to do.