Is wireless networks fast and reliable?

well that depends..
okay first of all, wireless networks can be very hazardous to users as it is a very open source of networking. Hackers are able to directly tap into your computer.(So you'll need a good firewall) but that goes with any network that has connection with the internet. Be also prepared for viruses!

Fast, you'll get instant connection with any computer within range, but please don't depend upon it to download hunderds of megs!

Reliable, depends on the software on the computer against hackers and the like. I find it very reliable when it comes to connection with other computers, but if your searching for large scale computing... its not a cheap business I can tell you that.