MacApper’s darling, ForkLift, is a pile of trash. I love when I make sftp file transfers and it crashes. Also, the only way to get multiple transfers at a time is to make multiple drags. Otherwise, you use a queue. You see, for certain servers I don’t get my full bandwidth per connection, but if I transfer two or three files at the same time this is somehow overcome and my pipe is filled.
Unison lets you do this by default for usenet, possibly because they realize that waiting on a transfer is not necessarily as efficient as allowing multiple to run should one slow down to 0 for some reason. As well, I don’t max my pipe unless I use two connections. Transmit (the FTP app from the same company) seems to work better now, it actually gets faster connections per file (somehow forklift was getting 300kb/s for one connection, and I only had the one connection, and Transmit gets about 650kb/s with non-concurrent transfers).
The reason I think forklift sucks is this: it crashes. A lot! During transfers! Sure, the last time I was forcing about 4 concurrent transfers, but that’s only to fill the pipe. Luckily I didn’t pay directly for it (I bought the mupromo bundle). However, AppZapper is surprisingly good. It actually makes it easier to remove broken/unwanted plugins and system control panels.