Penny,
If your going to dive the East side you probably want to stay down that end. I like Treasure Island because I can walk to alot of places for dinner and there is life there. Can eat for $5 or $50 depending on my mood. Basically it is at the start of the hotel strip on Seven Mile Beach. Nice sidewalk along the road so you can walk to Lonestar Bar and Grill (favorite bar) and a ton of other places.
I haven't been to the East side, but from what I understand it is very quiet and not alot down there besides a few hotels and the dive shops. The ride from Treasure Island to the East side is probably around 45 minutes, alot more in the morning as there is a major traffic jam headed into town every morning. Basically one road, one lane, and everyone is using it, faster to walk
.
On the East end I guess I would dive with Ocean Frontiers and stay at the Royal Reef. Other's on this board have talked highly of it but remember there isn't much life down that end of the island.
I have dove with Bob Soto and DiveTech. Bob Soto was OK, not great, not bad, as you know they have a shop at Treasure Island and typically their package price is decent. You can also book it as a package with your room and possibly save some money. Call Bob Soto direct and see what they offer. At one time for 6 or 7 nights (forget) and 5 days of diving with flight from Miami was $999. That was 2 years ago so probably has changed but worth checking on. Also suggest you get pool view at Treasure Island else you could have a beautiful view of an asphalt parking. Worth the extra $20/night.
DiveTech is a smaller operation but alot of people like them. I'm tech diving from shore and doing classes so can't comment on their regular dives. But I like their personal touch. They pick you up at 7:30AM. But I had no real complaints with Bob Soto either, other have. I think they tend to watch your skill level and then let you do your own thing if you look comfortable in the water. Dive computer is suggested. You can pick one up for $250 or rent one if you don't have one.
Suggest you post a question to Drew as he can probably give you some ideas of the better dive shops given he works at one.
Enjoy your trip,
Kev