It is mostly personal preference. Glass is less expensive by far, and easier to find. You usually have to order an acrylic tank. You also have to be more careful cleaning acrylic, it will scratch easier than glass. Either way, make sure you get a tank large enough for a reef setup (the bigger the better) as well as a good filtration system and protein skimmer and especially lighting. Honestly, you can get the tank/stand from a large chain store (Petco, Petsmart etc), but I would go to a LFS
or look on Ebay for the filtration, skimmer and lighting. The large chains dont carry very good units. If you are going to use an under the tank filtration system (wet/dry sump), make sure the stand youre getting will have room for it inside. There is a book called the Conscientious Marine Aquarist, which is very informative when youre just getting started. Hope this helps!