The 2000 is underpowered....when you're comparing it to a G4. The only time power becomes an issue is a short lag between FL360-390, and when using anti-ice at high altitudes. Otherwise, absolutely no problem what-so-ever!
The 2000EX EASy will have two batteries.
There is absolutely nothing wrong with flying it international. I've heard the RAT, battery, yada yada issue several times. I'm sure the G5 is a real bummer over the pacific with a total electrical failure (sarcasm....what are the odds?). I don't care if you're flying a Citation or 767 over water....you plan accordingly.
Eastbound to Europe shouldn't be much of a problem out of Boston most days. Westbound, especially in winter, plan on Ireland - Newfoundland - east coast. Summer time depends...conditions have to be favorable.
There are a few "high" time 2000's on the market in the $12-15M range. I promise you'll love this aircraft.
2000Flyer