We set up two bank accounts at Bank of Kigali. One is a RWF checking account, which has an ATM card. Couple hundred RWF per month fee. The other is a USD checking account, which doesn't have an ATM card and also has a small monthly fee. We tried setting up a USD savings account, and the manager said we had, but after a few weeks we noticed a fee and checked with him again and he realized that BOK doesn't offer USD savings accounts. It took him a long time (more than a week) to figure this out and to determine what the fee was as there is no documentation other than "fee", which he originally assumed was because we made our deposit in small bills (which we didn't, but it was all he could think of).
Our experience with banks in general (we checked a lot) are that they are generally poorly run (all of them), ATM machines go out a lot, there is no logical order when waiting for a teller (sometimes they use numbers, but sometimes they don't), there are always at least 6 people just hanging out in the managers office so it is hard to tell if you can go in and ask a question, nothing is available in writing even if you ask (such as the terms of your recently opened savings account), and you get a lot of mis-information from staff (a funny experience is to check something on a bank website and then go to a couple of their branches and ask the same thing and see how many different answers you get). These of course are the same issues at mobile phone carriers and other businesses in Rwanda, so if you're willing to be patient and know that your experience won't be quite the same as what you're used to, the banks aren't too bad.
Getting an account is really easy. ATM card takes a few weeks and you have to pick it up at the bank.
If you're going to deposit USD or other currency and have it converted to RWF, the banks give you a bad rate. Better to go to a ForEx and then deposit the RWF directly (or keep your account in USD).
Good luck!