Using Garmin Zumo390 with City Nav Europe map and special Motorcycle road map for Europe. Found the 590 having too may bells and whistles (and too expensive) for me. Also the cable of the 590 is huge (thick).
Be aware an updated series of Zumo's have been released by Garmin; 595, 395 and 345.
Also TomTom has an updated version, the Rider 410.
I am a very long time user of Garmin GPS devices. Strong point of Garmin is the PC based software BaseCamp. With BaseCamp you can makes routes and all sorts of others things on the PC and transfer it to the GPS device. You can also download routes from internet and transfer it to the GPS device.
If you are not familiar with BaseCamp and plan to use the GPS device mainly standalone, then the TomTom Rider 410 is the better choise. There is also PC software for the TT, but Garmin BaseCamp is far better.
Also the (European) navigation software of the TomTom is better. Curvy roads option of TT R410 is far better than of Garmin Zumo 395 and 595. With the TT R410 you can also very easily make a roundtrip. Oparating the TT R410 is also better than of the Garmins, this has always been a strong point of TT.
Huge price increase here in NL/ EUR of the new Zumo's. 395 costing EUR 600, 595 costing EUR 750...
TT R410 costing (only) EUR 400. Still a lot money though.
My next GPS will probably be the TT.
(CRF1000LAD, CRF Rally Red, Zumo390)