Team 360 is right about the Garmin/Magellan debate - it is likely to go on for a long time.
Personally, I started out by purchasing both a yellow etrex by garmin and a base sportrak (yellow) by magellan so I could do field comparisons of both. The etrex was a solid unit. I liked the convenience of the buttons on each side of the receiver. You get true one-hand operation with them. The sportrak can be operated with one hand as well, but it's a little trickier sometimes.
As far as user interfaces are concerned, the etrex is hands down the easier unit to read and understand. You'll pick it up and understand it in no time.
I personally think the etrex has a more solid feel to it. It just feels like it's well constructed. The sportrak wasn't a slouch in this regard, but the etrex felt a little better to me. I also liked the screen of the etrex - it's perfectly flat. The sportrak had a little bit of a "wave" to it. Small detail, but made a difference to me. The backlight on both are great, with the etrex offering one level and the sportrak offering two.
Reception-wise, they're both pretty good. Some will knock the patch antenna of the etrex becasue it loses signal in tree cover, but it wasn't all that noticeable to me. I took both on some bushwhacking geocache finds, and I thought the etrex outperformed the sportrak in terms of leading me right to the caches quickly. The sportrak lagged behind just a little (not a ton, we're talking about a minute lag). The sportrak has a quad-helix antenna, which I understand is more sensitive. It performed well in pulling in a signal.
Of course, it might not be fair to compare these two units. In addition to the quad-helix antenna, the sportrak has a built-in city database and is WAAS enabled, unlike the etrex. Depending on where you purchase them from, the difference in cost is about $30.
In the end, I took both back and picked up an etrex Legend. I liked the quality feel of the Garmin better than the Magellan, and I preferred it's performance in the field.
Don't know if this helps or not, but this is the process I recently went through. I guess I'm on the Garmin side, but I don't think you can really go wrong with either unit or maker.