I was uploading 800Mbit on both (on linux, because on Windows You have right chomikuploader have lower speed), but your program have more option, some of them I don't know how you made.
Service has unlimited file size but uploading works fine only for file lower than 1GB (don't upload bigger files). I think that this is because of program use HTTP protocol, if it would use ChomikBox protocol should be fine. I saw the same problem here in chomikuploader before version 0.3.0: