The colors indicate a little information about the user, and the connection...for example a red IP may indicate the user is behind a firewall, or is not available.

the best thing is to look at the IP, if its like 0.00.00.0 then
dont even try, there are assigned IP address to users hiding behind Firewalls, and antiHacker programs, these are NOT available to you, (see earlier postings for details) if your IP is stealthed

As for the connection color, it is suppose to help verify connection, such as a green T1 is really a T1, where a grey T1
cannot be verified, or is not a T1.

again this is just a tool, and is not bulletproof...

So the rule of thumb should be.....

1) avoid RED IP addresses
2) look at the size of the file (a mp3 is usually 4-5mg)
3) try for green connections, but be adventurious
4) start a couple of the same file, and abort the slow one

5) learn the IP address, if you get a file fast, look for more from that user, chances are youll get that fast as well.