Actually, there's quite a bit of difference. The 5300 is a 3x3 MIMO radio while the 5100 is 2x1. The 5300's max speed is 450Mbps while the 5100 is 300Mbps. The former thus has better range and transfer speeds. However, after testing quite a few radios (mini cards and routers), I find that the best ones are those using Atheros chipset. These seem to have best compatibility with routers that we commonly find (D-Link, Linksys, etc.) So if you want best performance, make sure both router and mini-card has chipsets from the same manufacturer.

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Added on August 25, 2009, 11:51 amAnybody notice the SXPS 16 has a WWAN radio built-in; there's a SIM card slot in the battery area and BIOS also refers to a WWAN setting. Anyone managed to get it to work? That would rock man...

I've come across older Latitudes, Asus and Fujitsu notebooks that also have a WWAN radio (mobile broadband). Slot in a SIM card and you can dial *99# to connect. No need to carry dongle. This feature usually not advertised as the notebooks aren't sent for govt approval, so they don't remove it but don't admit it's there.

So, anyone got it to work?