I should not be to concerned about the deposit coins. You have bitcoin, Litecoin and Dash.
As long as you have bitcoin to deposit, then it should be fine.
Well it all depends on the popularity of all the coins as bitcoin as the biggest one. i do not see that changing soon
I stick to bitcoins only. The deposit process is fine on the site. You get the funds added to your balance after 1 confirmation on the network. it could take a few minutes but also some hours, depending on the fee.