Yes, I agree. I wish I had not upgraded. They broke Cisco VPN, Tivo Desktop, and lowered performance a lot. Nothing new has been worth it.
I haven't upgraded yet, but I am getting a new machine shortly and I expect that it will come with Tiger installed on it. (My current PB is only 800 MHz and I wouldn't dream of trying to install Tiger on it.)
My understanding is that the Cisco VPN software was now available. You made a recent MemeStreams post about it. From the comments, it sounds like some people are still having compatibility problems with it. Did you try it? Is it causing crashes? I use the Cisco VPN client, and this would probably affect my interest in running Tiger.
I ran into this article about Tiger performance boosts, which I thought you might find interesting. Someone added a comment saying they did a clean install and found it to offer increased performance over Panther. Another commenter with the 1.67 GHz PowerBook also says that Tiger is faster.