I've used perennial geraniums in the past but grew wary of their self-seeding. Some of them literally moved around a garden from year to year. Rozanne (actually it seems 'Gerwat') is a sterile interspecific hybrid (also Plant Breeders Rights Protected). The previous likely best blue, 'Johnson's Blue' is also an interspecific hybrid, as is 'A.T. Johnson', etc., above and I'm guessing they're also sterile. It's very clear from GW that there's lots of perennial gardening styles within the same hardiness zone. Personally, I don't want perennials to pick their own location within a garden (unless perhaps to tell me where they'll grow best). The fact that Rozanne definitely stays put is another plus for such an excellent Geranium cultivar.

Geraniums do really well pretty much all up and down the coast. G. magnificum is beautiful but has a short season. Though I have only grown it on the east coast so it may last a little longer in the cool climate of the bay area.

I would caution on the Claridge Druce - I had it in my small garden & loved it for about 2 years until it reseeded EVERY where.... I had another year of trying to get rid of all the seedlings (& am still finding a few that hid from me last year). Much as I liked the long bloom & strong plant presence, I had to banish it. You did not say if you are looking for more "weavers" or what size -- and cranesbills definitely come in all sorts of sizes from 8" to 3' in height..... so you may want to decide on that before you choose some others w/ long bloom as well. I find that some while they do not continually bloom, if you cut back will definitely rebloom several times thruout the season in our area.

I've only grown a few of the ones you are asking about. G. maculatum 'Elizabeth Ann' - has been slow, but is impressing me more and more with age (her age, not mine, lol). This species is supposedly good with dry conditions, but I found her rather weak in comparison to her new home, which is moister. I have a NOID maccrorhizum (dark pink), not white. But you really can't go wrong with that species...tough, dry tolerant, and dependable. G. phaeum 'Samobor' I liked in my early gardening years, but not so much now. The small, dark flowers of the phaeums aren't to my liking (get lost visually). It also reseeds more than I care for- particularly when it does it in cracks and crannies of the sidewalk. The splotchy foliage is interesting, but that's where my liking ends, lol. 'Double Jewel' is newer for me. Got a start in a trade a couple years ago and it bulked up enough last year to make one flower, so can't comment much on it yet. Very mildew-y, but all the pratenses are in my climate. G. magnificum has some of the best and most abundant flowers of all I have tried (aside from renardii!). It has a lot of problems though. Flops in general, especially in a shaded site. Looks hellish after bloom. I know mxk3 has mentioned she has good luck in cutting hers back afterwards to encourage new foliage growth. Mine never rebound well after cutting...I believe it is because it usually gets hot and dry around here at that time. Cutting it back leaves a large gaping hole in the border for me for a long time. My advice would be to plant it behind or amongst other plants that have a later season interest to hide Mr. Magnificum. ;-) CMK