I don't see any security issue there. SSH is supposed to be secure and all the data are passed thru the SSH tunnel. So, yes, I believe it is secure enough. The only issue I see is efficiency. SSH is TCP protocol. TCP traffic is passed through an another TCP protocol. The packets are double "acknowledged" by the 2-layer of TCPs. Better protocols are built on UDP or even IP.
I've never used SSH tunnel like this. I have only experience with SOCK V5 protocol (ssh -D), and I haven't realised any significant network speed degradation issue.
Sorry for trolling, but I can't help myself... Unsupported windows platform isn't an issue for me, since I don't use any window :-)
