Like most engineers with a background in electronics, I've dabbled in some Sound Recording over the years, starting with a Tandberg 3041X 1/4" 7" reel to reel tape recorder. I bought this as a lower cost option to a Ferrograph or Revox, and what a mistake it was. If only reviewers would test machines over a sensible period, but of course, life's too short. I used mine fairly heavily for recording from Radio 3, and soon discovered that its rear-bias was very susceptible to tape quality, and not long after that, I realised that its heads were wearing very badly. I then found that the clutches were also giving trouble, and was quite pleased when someone had a use for it. This was followed by an elegant cassette recorder (Pioneer, I think) using twin direct drive capstans so that pressure pads weren't necessary on the heads. Once again, this was advanced technology with a limited life, and again quality soon suffered. My current cassette recorder is really a legacy item (Pioneer CT-S410), and now only used for replaying the odd cassette.
Much more interesting is my small collection of Minidisc recorders, from Panasonic SJ-MR230, through HiMD Sony MZ-NH600 to RH10 and RH1. In terms of usability, the LCD screen on the Panasonic is excellent with good clarity, and easily beats that on the Sony MZ-NH600 which is of low contrast. Neither is rear illuminated. The Sony RH10 and RH1 use OLED displays, and whilst very clear when used indoors, they are totally useless used outside even when the sun is obscured. The RH1 at least has a user interface which allows easy start recording, whereas both the NH600 and the RH10 force Menu opeations before getting into the recording mode. The Minidisc mechanism is relatively noisy, and prevents useful recording with a fixed microphone plugged in to the input socket. A cable is needed to isolate this noise. Their main virtue is small size, very secure data retention, and they can be used in a discrete fashion. Sony's bespoke software didn't help with live recording, and probably did much to kill off the use of these otherwise elegantly designed machines. At least the Minidisc recorders didn't suffer like the older tape and cassette recoders did.
Having realised that solid state recorders were now available, I researched and bought a Sony PCM-D50 in Winter 2009, and what an improvement! The display is fully usable, backlit on demand, and for my purposes the 5 seconds buffer feature captures unexpected wildlife sounds with ease. It offers a range of PCM modes, and will replay MP3 recordings as well as its own recordings. None of my recorders has support for phantom powering of pro grade microphones, but there is an adapter for the PCM-D50. Other valuable features for non-studio recordings are the filters and parallel recording (limiter) track at 20dB down, thereby allowing decent recording of unexpected peaks. (Less than 20dB above the normal peak level.) Moving recordings to my computer is now easy, and there's none of the earlier Sony Sonicstage nonsense where one's original recordings were only uploadable once, before being silently deleted on the Minidisc!! The preamps are very low noise, and the dynamic range is excellent so that low level sounds can be lifted with little loss in quality. It doesn't have an AGC.
Most of my microphones are Yoga, and I've made a simple Dummy Head arrangement using my own head as the blockage between the two microphones. I also bought and modified a very low cost radiant heater which came with a parabolic reflector, and have recorded birdsong with this. It reduces traffic noise, and the best blackbird song does seem to be in my front garden close to major roads.
The Minidisc Community website recommended the use of a 9V battery box to raise the clipping level, and to remove the need for the overloadable Minidisc preamp. Easy enough to build, and it works well, but I'm normally recording lower internsity sounds.
I suffer from otosclerosis, and my right ear is now quite a bit less sensitive than my left, and I wear a hearing aid to correct this. So that I can listen to stereo on headphones, I bought a SoundProfessionals Headbanger headphone amplifier. I added a variable attenuator on the left channel input, and suitably adjusted, allows me to hear well balanced stereo through headphones.
I use both Audacity (free download), and PolderbitS Sound Recorder & Editor (paid for download) for processing my sound files. Both have their virtues, and there's relatively little overlap.