Always feel free to play around there and test water at Sitex. If you do your homework and know your stuff, you will realise that you can get hilarious replies to your questions about the various cameras available at the show since most of the people selling cameras there know nuts about them. Not to say all though.
Alternatively, you can go play with the cameras at places like Courts, though it's not recommended that you buy from them.
If you don't mind being different, you can always check out the other brands. I was like you - only know about Canon and Nikon before but from reading up I realize other brands have a lot to offer too. Good luck with your purchase and always do your homework! Even some of the reputable shops at Funan may try to smoke you...