its actually working really well. some combination of the ATT rom and firmware,and some edits to build.prop i found to make att devices more consistent on t mobile have really stabilized my data.
the GF and i went to eat,then meijer and target,and ill be darned if it didnt read 4g the entire time. usually its spotty,and drops down to edge in certain places along the travled route.
my cellular network widget did show umts 3g occasionally,and the 4g icon didnt change,but it did show hspa+ mostly,and never dropped to edge. few speedtests got anywhere from 7 to 12 mbps down.
i hate to change it now its working so good,but im curious if all have the same results by modding build.prop on other ruus.
of course,i guess its also possible that t mobile flipped on the 1900 band on a few more towers making it a huge coincidence