We have both the Alpha with a high gain marine antenna and the one listed below. Both the Admiral and I have our own computers. We purchased 2 different systems for comparison sake.

I have found that the one from RadioLabs, listed below, gives me less problems. I don't know of anyone who's had a problem with it. Works on both PC's and Mac's.

It's more expensive than the Alpha but when you add a good marine wifi antenna to the Alpha it's almost the same.

The Alpha is good too (1/2 watt) and if you only use the small antenna it's portable. Reviews say that the difference between the antenna that comes with it and a larger accessory 7db gain antenna is tremendous.

http://www.radiolabs.com/products/wireless/wireless-marine-antenna.php