Don't overlook Tascam. I've had several. Currently using DR-05. I've used it almost nightly for at least four years now. Choice of WAV or various MP3 formats. Built-in mics are o.k., but I always used stereo line-ins from mixer or keyboard. I use rechargeable batteries, but on the job I usually power it via USB.
Hard to believe that something this small and inexpensive can make perfect recordings. Perfect that is, as far as what you put in, you get out.