Variegated leaves. The thing to remember is that the variegation leaves them slightly starved. They need slightly higher light levels--and yet ironically they burn more easily. Variegation also compromises hardiness a bit.

Other than that, they will act like normal Fuchsias. Usually if the variegation goes away it's because the "sport" that caused it is a mutation in some of the cells but not all of them--and the mutated cells die off faster than the non-mutated (which would not be surprising--the non-variegated cells are more vigorous). Just keep it healthy and you can clip off any shoots that revert, if you like. Fuchsias are heavy bloomers and therefor heavy feeders; I suggest feeding them regularly.

You are in a VERY severe climate for Fuchsias (you already know that I bet), so I suggest hardening it off carefully in mild weather. You might try rigging some kind of protection against late frosts and avoiding severe exposure.