Luckily i have an account with Beatport and as an independent label we do really well of there, The way you submit material is different and easy to use, They have been a bit shaky with payments but this is due to $ to £ situation.

Juno are really good, They have just started pushing wavs more which imo is the way forward, Better sound quality and more money for the label and artist, upload easy.

Trackitdown are ok, there upload is a nightmare and does not work very well most of the time, only been using a short time so not much to say.

Im not sure what stuff you will be selling but Addictech.com are good, have a very good collection of labels on there now and is doing very well (Based on the west coast US)