I (Lanny Chambers) formerly used one of these feeders. It was replaced in 1997 with a HummZinger. The Perky-Pet 210-P is a very popular and inexpensive (street price ~$8) feeder, comprising a 16-ounce clear glass reservoir with a screw-on cap for hanging and a red plastic dripless base with four small, flat, yellow plastic "flowers" defining the feeding ports. The perches are rather fragile: I managed to break two off in the course of normal handling. Replacement parts are inexpensive, but I've never seen more than two birds at this feeder, so I never bothered to replace them.
The 210-P really is dripless. I replaced the yellow flower pieces with red ones, available from Perky-Pet, and they do seem to be less attractive to bees and wasps. I don't know whether this feeder is inherently attractive to hummingbirds, or if they have learned to recognize it from experience, but the 210-P seems to be very effective in luring visitors. However, the HummZinger is much easier to clean and is inherently wasp- and ant-free, and its increasing popularity means that many/most hummingbirds now recognize it.
The main problem with the 210-P is its complexly-shaped base, which does not disassemble for cleaning; this makes inspection and maintenance difficult. Once mold starts to grow inside, a bleach soak (see the Feeders section) is the only sure way to remove it. The bottle is also difficult to clean, due to its shape, but it's much less prone to growing mold than the base.
69 North Locust Street
Lititz, PA 17543