Friends,
Let it be Flashget, GoZilla or DAP or any download accelerator. If you study the method they operate the actual question of comparison will not arise at all. As for as download speeds are concerned they are dependant in the following factors.
The Bandwidth through which the download server is connected
The Number of users connected to the download server while you are downloading
The Bandwidth through which you are connected with the Net
The number of users connected with your ISP at the time you are connected
The Location of the download server or the number of hops from your IP to the Download servers IP. The lesser, the Better. The next time you try a server try ketying the following command in your Start-->Run--> command line
TRACERT https://yourwebsite.com
and see the route it takes to the server.
Most of all, the ability of the server to resume downloads
The simultaneous number of client connections allowed to the server from a Single IP. Mostly it will be a maximum of four.
Now lets see how all this doenload managers work. They all connect with a single thread to the server first. Then the Accelerator queries the server for the resume support and then it communicates for the simultaneous client connections and if the server supports more than it sends further requests to start simultaneous connections. Now, the actual intelligence of the softwares is to split the file in to the number of simultaneous connections and once downloaded it re-assembles all the files to create the actual file.
I hope this doesnt confuse a lot, but My opinion is that all the softwares can produce only a similar result. As for as Flashget is concerned, There are two advantages. Number one, it shows the clear activity happening through a log and most fo all, its easy to crack.