AT&T Laptop Connect card

I'm getting one of these on Wed. The website has about 5 to choose from from "Option" and "Sierra" (neither of which I've ever heard of.) They all say 3G on them and claim to do hsdpa and edge. The do differ in appearance, especially in how much of the card sticks out the side of the computer (I'm assuming this is the antenna?).

Before I blindly choose a card, does anyone have any experience or advice to offer? Will having the bulky external antenna give me better reception?

Just wondered if any of you have any experience in this area. Also, are there any convincing arguments to just use my Treo 650 (EDGE only) instead?

Most of the 3G data cards I've seen in the UK are rebranded Option ones. It works okay but the software is a bit clunky and buggy.

my buddy just got one that is usb, and has a sim card slot which I thought was neat. that way you can just take your sim out of the phone and put it into the usb card and not pay an additional $50/month. However I don't know who makes it