[quote name='panasonic']i had one of these, it got really slow speed and disconnected after around 2 hours. Have you ever had it disconnect? Recommend me buying another? i do need an adapter[/QUOTE]
I haven't had a single disconnect with it, playing Final Fantasy XI on the 360 for hours on end (and I'm just connecting via an ad-hoc wifi network with another 802.11b adaptor, no dedicated router).
As for it only being 'Wireless B', that means it transfers data at 11MB per second. Range is virtually identical to G (around 100ft; 802.11n which doesn't hit until 2008 increases range to 160ft). They can operate farther away than that, but at slower data transfer rates.
Anyways, what I was trying to get at, is that while the difference between B & G might make some notable difference transferring files from one PC to another over a wireless network, it's going to make next to none for online gaming over current broadband connections. Residential cable only ranges between 384kb and 2MB, with DSL somewhere below that in most cases.