I am currently using the following equipment for low volume and occasional BGA rework: BGA-3591/CSP-3501 115V Rework System. This system is fairly inexpensive, unsure of the actual price, However, can be used to rework QFP and PLCC components.(of course specific size nozels are available at additional costs)
We use SRT. We still have machines that are over 5 years old and are functioning very well in the BGA, QFP and yes CSP area. The critical part is getting the right Air nozzle for the part size. Also the software has a auto-profile feature that works quite well.