Electrum/thread
i mainly need:
fast sync,
Electrum is SPV and has a very fast syncing process...
a way to control transaction fees with no limit, at multibit its 50k satoshi
Has "Dynamic Fees" to suggest the best fees for fast confirmation (tweakable with a simple slider at transaction creation time)... and you can even set fee manually if you want ultimate control.
easy backup
HD wallet... you just have to "backup" the 12 word seed and you're done
and the most important that i will be able to use it in the next few years and will not get stuck again.
Going to be hard to get any guarantees on this one for any software... Electrum is open source, so even if ThomasV disappears, I'm sure it will live on... it's very popular