i found it so much easier to process and get more out of data once i got one. i'd definitely recommend looking into it
for example on a regular dslr image my max sub would be 70 seconds (at f4) after getting an astronomik cls ccd i could go to 3 mins. thats a fair difference of good signal vs bad signal. of course you need to get spacing to work.
nice, interesting stuff with the derotator, i was considering it once for my dob,
but it was getting complex with the changes in speed at varying altitudes.
although now a few years later with the new cmos cameras they are probably fine in alt az with the low read noise / high gain.
however all in all its a great result as is so there is definitely no rush for the filter just yet!