Thanks for your kind words. Our developers have worked VERY hard to make the UI as fast, simple and clean as possible. We have a long way to go - our dev roadmap has more than 300 items on it.
Every single thing you mentioned is already on our roadmap, particularly the language and currency options.
You can already accept check or cash payments manually in the system right now (as you may already know). You could also create bookings manually and then accept the deposit as check or cash manually.
In a few weeks, we will be beginning work on an overhaul that allows owners to be check or cash ONLY. In other words, you won't have to have a merchant account to use the system. You can have guests accept quotes and send checks or cash instead. Security deposits and scheduled payments will be reminder emails instead of auto-credit-card transactions.
Our biggest frustration is that we cannot move as fast as we would like to.
Thanks for your patience,