Did somebody try the Marantz PMD620 with an external mic?

Yes, the 620 sounds OK .. depending on what you want to record. You will need a good windscreen if you plan on using it outdoors. Not as versatile as the H2 with it's Front/Rear and other options IMO.

Of course neither can compare to hi-end stereo mic set-up.

I did when I owned one briefly. It was a big improvement but I settled on the Sony PCM D50 as offering better audio both with onboard and external mics.

I misread sorry. "Extermal mic". No, I mostly use line-in for camera audio back-up.

PMD-620 Modifications (http://www.oade.com/digital_recorders/hard_disc_recorders/PMD-620MODS.html)

Would anybody who ships to Europe supply the same kind of upgrades as under the above link?