Does the Samsung support voice and data at the same time on 3G like the new EVO? I have the original EVO, but HATE the charging port on the side(and manufactures wonder why charging ports get damaged) and the non-removable battery on the new model. Also does the WIFI work better than on the original EVO? My EVO constantly drops my router, and 10 seconds later reconnects. Makes it tough to listen to Tune In Radio. I do not have this problem with other devices, so I don't believe it is a router issue.
The new EVO and S3 will connect to data and voice when connected to LTE. You can be connected to WIFI and make calls and use data. Will not work over 3G. You must be having problems with your EVO 4G when staying connected to WIFI. Mine works great. No doubt the EVO LTE is the best on Sprint's lineup.