I also only use IGM and FirePay.

Last I checked, NetTeller--unlike Firepay--gives you the option of doing a "non-instant" deposit (it takes a few business days to go through). This option is either free or has a very small fee. But if you do want an "instant" transaction, then Neteller's fee was more expensive than Firepay's. Thats why I went with Firepay.

I always just make up a number to put as the "check number" whenever I do an online check transaction.