I like Vanguard a lot. As you say, the UI is nice and simple, and the great timed stuff still separates it from other synths. The only two downsides are that it seems to clip/pop easily and the built-in reverb is harsh. Not too difficult to work around.
Also check out Sylenth1 from Lennar Digital if you are on an Intel Mac. I tend to "get along" with the UI and it sounds great. GForce Minimonsta, and u-he ACE and Zebra are also worth a look and listen.
Thanks a lot for your input!
I wound up buying the Vanguard. Now I'm struggling a bit with myself in applying it to a song - I wanted to have bit of fun with the step seq / arp, but keep leaning annoyingly much to much too conservative choices (a have a kind of gritty guitar part that I'm trying fit it with, which turns out to more difficult than I expected).
I liked the other synths you suggested as well, particularly the Sylenth1 which I think I might buy as well - It had a nice feel to it.
Don't know about a dll, but there should be a vst or rtas file in there somewhere. Running on a mac myself, but I seem to remember just getting the plugins to install. Perhaps the the exe does that for you, but shouldn't the be some resource as well then?