I'm not an expert when it comes to device handling on Linux but I have written udev rules in the past (since 071 and earlier) and do have some familiarity, and at the time udev was first introduced it looked like an excellent solution. In fact, I felt it was a welcomed change from devfs. Not so long ago time came to upgrade to 105, and boy was I surprised - these days udev really looks like shit.
It sure doesn't seem like udev's design has scaled very well. For instance, udev rules you wrote even 6 month ago are unlikely to work with the most recent version because they keep changing the syntax every few releases. Why would stuff like $modalias suddenly be changed to a much uglier $env{MODALIAS}? I'm curious to know why anyone would favor such a syntax.
Also, udev 071 consisted of a fairly small set of binaries, but later releases grew to pretty much one helper program for each device class, and you are now expected to do stuff like copy pre-made symlinks and device nodes manually into the /dev directory. If anything, wasn't that supposed to be udev's job in the first place? A nice improvement is that udev 071+ completely replaces hotplug for the 2.6 kernel - which is perhaps the reason for all the helper programs.. I'm not entirely sure. I still think it could have been done a lot cleaner, though.
udev rules used to be something that could be written in a very clean and comprehensible style, but now you'll get a headache just by looking at basic examples. Quite frankly I'm starting to dislike it more and more and sometimes find myself wishing for it to just go away. After looking at FreeBSD and how clean /dev is kept I'm starting to wonder if it really was such a great idea to abandon devfs all together.
Update:
The above is an old post. Since then udev was merged into systemd - a rat's nest of a init system that I'm forced to use daily, fortunately the eudev fork exists.
