I like All-Glass products just fine. I have had 8 of their tanks over the years, mostly 20 gallon longs. They make a quality product and I have never had a problem with one. I also like the versa top because it gives me more options as far as lighting goes. Since I am a planted tank buff, I need lots of light. I would suggest staying away rfom the high output compact light unless you decide to go with a planted tank. Fish look fine in surprisingly low amount of light, but plants have to have better light for photosynthesis. For a 55 gallon you could easily get by with 30-40 watts of flourescent light for nice viewing. If money is a concern, I say buy used. There are certain things you should be careful of when buying used.
I would ask first and foremost if it leaked. Also, ask them when was the last time they had it set up. Ask them if it was fresh or saltwater. Ask them if they ever housed a reptile in it (this is important because they would not have had water in the tank.) Ask them if you can fill it up with water and if it leaks, bring it back. Get that part in writing. Something as simple as "Tank won't leak" on a piece of paper signed by them should suffice. You want to inspect the tank for scratches and make sure there are no chips in the glass. Also, make sure the trim is intact and looks in good repair. Also, check the silicone in the seams. if any of it is flaking or otherwise loose, it may not be the best tank for you, unless you don't mind reparing bad seams. If you feel up to that, be sure to point out to the seller that the tank looks rough and you'll have to redo the seams, then try and get them down to a much lower price.
Then, test that tank out somwhere you don't mind 55 gallons of water leaking out. 55 gallons is a LOT of water. It could flood a living room an inch deep in water, destroying your carpet, padding, and anything that sits on them. I suggest a carport, backyard, back porch... anything like that. Make sure the tank is level and flat on the ground. Fill the tank all the way up. Don't be shy, some leaks occur on only the top inch or two. If it holds water for a few days, chances are you are in luck. you can drain it part way and then begin cleaning. I suggest a bleach solution of about 9 parts water, 1 part bleach to clean and sterilise. I like bleach because it is made of chlorine, and as a fish nut, I have dechlorinator on hand to make it safe. After that, rinse it in water that is overdosed in dechlorinator a couple times. Leave it out in the sun for a day or two to air dry afterward. The sun will break down the chlorine as well. After that, clean whatever equipment you got in a like manner, if it was used, then start setting things up for the cycle.
As for how much it will cost, well, on a new set up you can usually figure about 10 dollars per gallon of tank. So $550 is a decent aestimate for a 55 gallon tank. Buying used, I'd half that, but I am picky about equipment and lighting, so you could get into a 55 gallon for even less if you luck out and find it all used and in great shape.