i guess it really depends on how serious you are,
you can still get superb images with a colour camera as seen in this thread here:
http://www.iceinspace.com.au/forum/s...ad.php?t=33564
while the colour version might not achieve the same resolution as the mono, it would be easier to use and this can become a factor.
instead of being limited to x amount of time per filter you can use that time that you would have been changing filters to shoot more frames.
another thing in favour of the colour version is less processing, you wont have to process separate avi's then stack the result to produce a colour image.
the mono version would be a fair bit more work involved but if everything is going your way it has the ability to produce a sharper image, also you could use it to do false colour imaging like imaging mars in IR or venus' atmosphere with a UV pass filter which makes it a bit more versatile.