Help! Portable Audio Recorder - Zoom or Sony

I'm looking for a portable audio recorder (built in mic). Needs to be good for numerous things - recording me playing piano, organ, possibly concerts (as diverse as rock, choral or orchestral - in good quality!) and needs to be rugged as I intend to use this in school (teaching music).

I've spotted two - the Zoom H4 (around £200) and the Sony PCM-D50 (£270 on eBay). Has anyone had any good/bad experiences with either of these?

Is the superior quality seemingly afforded by the Sony worth the tradeoff to the multi-track and XLR inputs from the Zoom?

O, people of IMM - HELP!

Also, see here for reviews/useful info on the above (and more) recorders of a similar nature...

http://digitalmedia.oreilly.com/audio/portable-recorder-comparison/

Click on the recorders for in depth reviews.

Zoom is much better! I use it in my work and recommend it to people all the time.

What sort of things do you use it for?

I work in a forensic audio lab. But I'm a linguist so I also recommend it to academics using it for field research. That is mostly speech-related but I have musician friends who use it as well.

Blimey, quite a recommendation then! I'm still, despite the higher price, leaning toward the Sony - it seems more rugged, and other reviews (and my own ears) say the sound quality is better. The multi-tracking on the other hand...

A few more good Zoom reviews though, and I could swing back. Anyone else used it? Or the Sony?