This recorder has a lot if features, which comes in handy for the traveller: Compact size, driven by ordinary AA batteries or AA rechargeables, long battery life (at present the best of all the pocket recorders), built in mikes flush with the surface = less danger of damage and easy to pocket. It seems to be rugged. I have good experiences with the durability of other Sony gear, for example an ICF-SW7600 radio, which still works perfectly after 20 years of travel and use.
In addition to sound recording, I use the M10 as a convenient MP3 player, so I have one less gizmo to carry. It doesn't have an EQ, but the output sound is fully acceptable as it is. The output power drives my full size AKG K240 headphones without problems. The M10 will connect to almost anything. With its USB plus line in and line out jacks,it hooks up with the PC, with the stereo, with the kitchen radio, with external PC speakers, with PA systems etc.
It records directly to WAV or MP3, so it's also excellent for digitalizing vinyl recordings, recording radio broadcasts etc. for an IPod.
When coupled to a PC, the unit is a simple external drive, making file work easy. You can edit the files on the M10 from your PC.
The button layout has put off some people, but I find the button concept easier than navigating through menus for every task, and the buttons work very intuitively for me. Some have found the menus awkward, but I could use them with ease from day one without looking in the manual (two things real men don't do: Read manuals and make backups :-) ).
I haven't tested the sound quality compared to other recorders, but it's absolutely fine for me - and the pro reviewers finds it more than OK too.
The MR-1 does have a built in speaker, but it's mono and its max volume is so low that it's useful for nothing else than making sure a sound has been recorded at all. For anything else, headphones or hooking up to some kind of external speakers is necessary. But many pocket recorders don't have speakers at all.
There are some things this unit won't do:
It doesn't have XLR input and no 45V Phantom Power, but that would have made the unit more bulky, and one of the very virtues of this unit is the small size and the rounded and smooth shape. If XLR is a must, check out say the Zoom H4N. The Tascam DR-100 also has XLR, but it's battery life is too short for my taste.
It can't do multitrack or sound-on-sound, doesn't have guitar effects and amp simulations, has no guitar tuner and no metronome, so it may not be the recorder for the musician who wants a pocket studio or practice tool. Here the Zoom H4N, the Boss Micro-BR (mulititrack) or the Krog SR-1 (S-O-S) may be a better choice. Myself, I play guitar and I use a now discontinued Boss BR-860 recorder for home practice (much the same as the Boss Micro-BR, just far bigger).
And oh, the M10 doesn't have a FM radio. There is one in my cell phone - I have never used it.
But someone on the move who wants to record sounds around him whereever he goes and wants to hear his favorite music everywhere without carrying around more than one unit will have a hard time finding a more convenient recorder. It simply handles good. When I use mine, it gives me the same comfortable feel as a pair of well worn slippers.