Jim - if you have space, they are great to grow, as I'm sure you well know. I have two large clumps of them and hubby didn't realize one of the clumps was my daisies, he thought it was some sort of out of control weed
, so he weed whacked it and it STILL put out a large show of flowers (though with shorter stems). Hardy flowers, they are. Great for bringing indoors and putting in the center of the table to enjoy looking at over dinner.
Elena - I would say mine get to about 2' tall...sans weed-whacking, that is
(see comment to Jim). I highly recommend trying them, especially if you find yourself lamenting having so many daylilies and not enough flowers. (I don't always cut ours, though, and sometimes just enjoy them growing outside so I deadhead them in order to produce the second flush of flowers they will give you.) As Jim mentioned, they have a really nice, long bloom period.