Thank you, a very good question!  And to be honest, right now I'm not sure I care (famous words of desperation!).  Perhaps foolishly, having patiently tried bitcoin core over and over, I do feel quite desperate to free up my coins as there is something I'd like to buy.

I don't really have a long-term wallet choice yet.  Perhaps electrum.  But right now to get started, I just want anything that will give me access to my coins locked away in my encrypted wallet.dat, and worry about what to do with them once I've got that far.

That's why I thought I'd post here for some voices of experience.  I've been dipping in and out of documentation for the popular alternative clients and to be honest it's sending me slightly crazy.  I haven't seen any import processes described that I fully understand, some favour coin xfer not import, and really I'm looking for something idiot proof like copy your wallet.dat here, or paste your pywallet dump into this box etc.

So I'd really appreciate any advice along the lines of "well if you pick client X this is dead easy, just do Y and you'll have access to your coins".  Priority is ease of import/access.   Security I can think more about later? And if it all goes wrong and my coins are stolen, I'm not worse than I am now, with a wallet.dat that I haven't been able to do anything with for many months!