Polyesters sound different than polypropylenes, and polypropylene film sounds different than the metallized variety. Of the metallized variety, which most end up using -- some of the inexpensive brands impart an etched quality to the high frequencies. Solens are a fine example of this and I'll only use them in low pass sections. I do agree with some of what Erik is saying, for example; the Hovland, which is a very good film type -- can really wear on the nerves after a while in Klipsch tweeter filters.
Auricaps, Kimbers, Sonicaps -- all of the quality metallized types sound a little different to me. It very well might just be in my head, but I notice it nonetheless -- and I AM a sucker for caps wrapped in yellow tape.
I consider the Daytons to be a pretty decent entry level type, but I would use the Jantzen Z-Standard for a budget cap in tweeter filters. They come in 1.8uF and 2.2uF, and I would go with the 1.8's. The great majority of caps run to the high side of their stated value, and just about anything marked "1.8uF" is going to run between 1.85 and 1.9 -- plenty close enough. I have no problem using 10% 12uF caps for Klipschorn, LaScala, and Belle networks. I've never bought one that after measuring didn't put me within 5% of the needed value (13uF). Really, in the world of first order filter sections even being 20% off the mark probably isn't going to have much impact.
I still say that if you're going to go through the trouble to do your networks, live a little and get pretty yellow caps instead of ugly black or white ones. )