Layo ra kaayo ug price diff ang 500D compared to D90 brod, 47k vs 66k? Although mo-compensate lagi ang newer lens sa Nikon nga naa nay AF (some), pero it's more convenient to use kanang naa nay built-in ang body ug AF daan.
Ang camera weight is just a minor setback, later on you'll get used to it, besides basin bug-at pod lens gi-mount adto imo na-testing compared to the kitlens attached to the other brand
In the end those two models ur choosing are very good ones, if asa ka mas comfortable and asa k makakuha ug resource then kadto nga unit palita =)