This is what my years in MD have given me as advice. MZ-1 - It's large, with poor battery life but it is so well built it doesn't matter MZ-R70 - The build quality is amazing, 2 headphone outs, the only problem is the battery door tends to not stay shut flush with the unit after a few months of heavy use. MZ-R50 - High quality, the first top of the line recorder that really made MD something worth investing in. MZ-R90 - The best unit ever made. Even with upgrading past this unit to the R900 (I had many problems) and the N10 (the unit netMD function died within a year) this is the last top of the line unit with amazing build quality that lasted through years of heavy use. My unit was stolen but I would love to find one for under a hundred dollars still. sigh... MZ-R900 - Good unit, but I had the problem that was reported with many of these units that the audio playback skips because the lens to the recording head dies a lot faster than other previous MD models. I did a lot of recording and about a year and a half into the unit it died. If it's used, I would avoid buying this unit. MZ-N1 - I never owned this unit but I've heard very good things about the build quality. MZ-N10 - within a year expect the main board to the unit for the PC to MD to break. I'm not the only person to have this happen for it's rather common. Other than this the unit is highly durable and regular 'old school' type recording works wonders. I replaced MD for the NW-HD1 which just died. I got 500 USD back from CC because it was no longer replaceable and plan on cuting loose from the HDD market and going back to MD. Replace the N10 through Sony online and get a Hi-MD unit. The only other unit that I've had is the MZ-N707. I can't stand anything anymore unless it's the top of the line unit. They are large, have poor build quality, and lack features. The bottom of this unit is plastic (ew) and I've had a problem of the screws falling out of the unit which doesn't make any sense. All it does now is sit next to my computer to record and I use my N10 as a portable player. I've always been an amazing MD fan. Before MP3 players became more affordable with more capacity than 128mb for around 300 dollars MD was the way to go. I now use SonicStage on my computer hooked up to all of my dj gear and audio equipment. If you want a player for the good ol' times, get one of the above units that are pre-Net-MD/mdlp. If you want something better for use with all of your audio and quick transfer from your computer, keep the N910 but get a Hi-MD device. ATRAC has really grown into something amazing over the last year and a half and Hi-MD takes advantage of the encoding ratios. Other than that advice, that is all that I can say upon this subject.