Sorry I'm late to this thread...
Been using the T-Mobile in the DC area (live in Potomac, MD and work in Vienna, VA) for a week. No problems at all connecting by GSM and GPRS. Nice, high speed GPRS web surfing is a dream!
Used VoiceStream now for over 18months in the area (GSM) and never had any problems at all. Coverage extends all the way to the Eastern Shore; had outages in rural VA (horse country).
Hope this helps!
