The Suprima 30 is a great little boiler IMO except for the PCB issue, if you're on the final revision PCB (Came in an update kit and is identified by being a grey, modular item with new harness) then you shouldn't have anymore PCB issues - Not changed any of the new ones as yet.
As for the gas valve - Its a Honeywell which is a good brand; once changed there's hardly anything else to change so it sounds like you've managed to get yourself a "Friday" boiler. if ya know what I mean.
So far, as a break-down engineer myself, I haven't had the pleasure of working on any of the Suprima HE appliances which is normally a good sign. But they have not yet been in production long enough, nor are they widespread enough to truly say whether or not they will "go-the-distance"... If you are after a good condenser; I would suggest the Performa HE and have it down-rated to the 12kW you'll be needing if the current Suprima 30 has enough juice for your property. These are much more wide-spread in the market place and as such, have proved themselves to be a reliable piece of kit in the field.
Obviously; this is just my personal opinion... I generally avoid installing appliances that have not been "field-tested" simply due to the fact that I like to know what I'm offering my clients.
Best of luck in the final decision.
GasAid.co.uk, January 2007