I'm extremely pleased with this unit. From a noise and distortion point of view, it's great - the inputs are very forgiving (i.e. very large signals are needed to overload the first stage), but I love that the sensitivity settings are in 6 dB steps (and there's a fine-adjust as well). I'm a fan of known steps in a gain / attenuation setting, so from a set up / repeat set-up perspective, it's a time-saver. You do tend to go through batteries when phantom-powering four mics at a time, but that's to be expected. However, one cool feature is that you can dial in the external DC voltage that you plan to use (it's a user setting), so whether you are running from the batteries, wall wart, or an external DC source, you have a lot of options to power the unit.
My only gripe with the unit (and this is minor) is that the high-pass filter setting only goes down to 40 Hz - I would have preferred a 20 Hz setting, but perhaps this is something that could be updated and the unit re-flashed (firmware).
I bought these to replace some Samson Zoom H4's that I had, and I did so because I wasn't happy with the unpredictable nature of that unit's inputs (as well as their max input voltage). This wasn't an issue for most jobs, but the R-44 just has a much more solid feel to it than does the H4 (I know those have been updated, but frankly, if you need a four-channel unit that is a tremendous bargain, then I would suggest checking out the R-44).
I can't say much about the built-in effects and such as I really don't use those things as a rule, but again, if you want a solid, reliable, affordable, and well laid-out recorder, I would strongly suggest that you look into this. Plus, you can sync two units to get 8 channels of recording. That's a plus. Oh...one more thing...there's a buffer as well, so if you set up the recorder to enable this feature, if you "miss" the start of the recording, you really haven't missed it all all as the recorder will pull a few seconds from the buffer (the length and time available is user-set / depends on the channels, sample rate, and so forth). This is very handy (and comforting) for those gigs when you might be distracted, away from the recorder, or the band starts ahead of schedule - a very important feature for those "one take only" gigs.