I have the one with the Yashikor and have had excellent results with it, so if you're keen on comparing, we could trade prints. Personally, my first error was that I didn't know that you need to push on the advance knob to go to the next frame. I though my camera was broken after the first frame...
If you want to use a cable release on it, you'll need an adapter (called a "Leica nipple") to reverse the threading around the shutter button.
You can shop for Rollei Bay I filter if you really want, but I suggest you rather invest in BayI - threaded adapters. I use a BI-49mm adapter when I want a yellow/red/etc filter.
I use it as well with a 49mm thread square lens hood on the adapter. Try to find one if you can, because the round ones will cover your viewing lens. They're better than the original bayonet hoods, and they will cost you way less. I haven't noticed any vignetting with adapter+filter+lens hood.
The accesory shoe is reversed from a normal accessory shoe, so that the stopper goes behind the flash instead of being in front of it. This causes problems when you have a flash that does not have a continuous groove on the sides (I think those were made to put on accessory shoes without any holding mechanism). For now I spent 10$ (canadian, of course!) on a flash bracket to hold my flash.
I take the habit to advance the film AFTER I've taken any shot. That way I can rest assured that whenever I pick up the camera I am ready to shoot. You can do the opposite, of course, but the important thing is to have a system that equates picture taking with film advance. Occasionally I forget, but then I willingly advance, because I prefer losing an unexposed frame than an exposed one.
The self-timer on these camera shutters tends to be flimsy and I've heard that some people have jammed their shutter from using it. I didn't have any problem with mine, but I use it very sparingly.
Some people also lock the M-X flash synch (M for bulbs, X for electronic flash) into the X position because it's easy to kick it by accident when you are adjusting aperture.
Avoid at any cost changing the shutter speed once you've cocked it. You can damage the mechanism. Again, I've done that by mistake and my camera didn't explode, but try not to.
Double exposures ARE fun!
) It won't bother and/or amuse you until the first time you're trying to follow a moving target. 
