There are always endless threads about wifi with lots of opinions. I have both the Engenius and Alfa USB client adapters and the Ubiquity Lightstation 2 client bridge (equivalent to this is now the Ubiquity Bullet sold by Island Time. I have been using all three of these systems for 3 years up and down the East Coast US, Bahamas and throughout the Eastern Caribbean. If you REALLY want internet access, the Ubiquity system is the only way to go. These are not toys - they are professional equipment used in all commercial wifi AP and mesh networks.

Offshore, if we are within 10 miles of line of sight access to a shore-based router, even one buried in someones living room, we are connected. Really. We had almost continuous connection between the Virgin Islands and St. Martin sailing past Statia, St. Kitts, Nevis, Monserate. Off the coast of New Jersey, we can Skype 30 miles out when we go past the resort beaches, which beam strong signals from the hotels toward the beaches (ocean). In harbors, 3 mile connections are the norm. And that is even more impressive given that we are usually connected to a low-power consumer router buried in someone's house.

Our Ubiquity is connected with a 9db antenna and located 15' off the water. The key is to use a minimal amount of coax to connect the antenna to the radio. Long coax runs are what kills performance. If you are using more than 6-12 INCHES of coax, you might as well give up. The Ubiquity bullet gets rid of the coax altogether by packaging the radio directly to a male antenna connector able to take a mesh antenna.

Antenna height can make a difference, especially if you chose a high-gain antenna with narrow beam width. I have found more problems undershooting connections through routers located up on hills (especially in the Caribbean) than overshooting connections at shore level. In my experience, higher is better and 9db is good, but I think it might be improved a bit with 12db.

Keep in mind that if you get a 800-1000mw radio and connect a 9-15db gain antenna you will be breaking the transmit power law in most all countries. But I don't know if anyone cares or has anyway of knowing. You are also breaking the law if you connect through private unsecured routers. Your conscience will have to be your guide here.

Just one person's long experience with all of the commonly available technology...

Mark