There are no cons.

It should be cheaper, although you may find one or two Blu-Ray playes cost the same depending on the PS3 model you get (i'd recommend 60gb if you plan to use it for gaming, especially with PS2 games but 80gb is a good alternate).

It will play all Blu-Ray movies, not just now but also in the future as PS3 firmware updates will add new Blu-Ray features and such updates will also allow larger capacity discs to read with no problems (as some standalone players can't be updated so will need replaced over time or will end up being behind on updates and features and unable to play certain movies if they are using these higher capacity discs).

While all Blu-Ray players are able to play DVD's, but not all play CD's so the PS3 would give you extra disc formats that can be played.

Plus you will be able to use all the PS3 functions as well because having the PS3 could open new possibilities for you if you plan to using it as a console as well.