Switches and Protocals, Compared

["E. Lee Dickinson" <lee@xxxxxxxxxxxxxxxxxxxxx>]

Okay, I've been trying to find a concise comparison between various dimmer
switches using the various technologies.

The switches must have the following capabilities:

1) Top/on, bottom/off
2) Local dimming
3) ramp up/down
4) preset dim
5) resume dim (preferably)
6) 600w or greater load capacity

2-way isn't really necessary for me, though it'd be nice. Scene control
isn't, since my computer handles that.

In ascending price (and I assume reliablity) order, it seems the options
are:

Smarthome X10 Switchlinc (~$35)
Smarthome Insteon Switchlinc (~$70)
ZWave ($75)
UPB  ($75, but I figure you'd get the $80 universal base for flexibility)
RadioRA ($150)

The Smarthome Switchlinc (X10) really only has a significant price advantage
when you get the basic version. If you get the 2-way version with scene
settings (making it a more comparable product to the rest listed) it's right
up there with the others.

So.

What am I missing? Can someone fill in some details about reliability, where
to buy, what to know about pros and cons of each technology?  I'm having a
lot of trouble finding a comparison in one place.

Thanks for your suggestions --

:Lee