Do you pay a fee by default or no? What's keeping you on .15 instead of upgrading?
I don't pay a fee by default, though if there's any possibility that a send might create a large transaction, I'll add a fee manually.
I don't find the features of later versions to be necessary for my usage. Unnecessary changes = insecurity and instability. My 0.3.15 client does not have 8333 forwarded to it: I run 0.3.19 (with a few added changes from later versions) on my Internet-facing client.
I'm thinking that I might start publishing "stable" versions of 0.3.19 and 0.3.20 with bugfixes backported. Feature changes are happening way too fast.