Having used to own one I can tell you plenty. For one thing, these scopes are a tad bit more forgiving in a light polluted area than a reflector. I have taken mine to dark sites (no higher than 3200' in elevation) and I could reach Mag 10. However, in my opinion mag 8 or 9 is perhaps it's best overall maximum. Planet wise, its' a great scope...very sharp. They come on CG-5 mounts that are too "small" for this scope, but you can "modify" this problem. The mount must be regreased and deburred and wooden legs installed after removing the hallow aluminum legs. These modifications can be seen on the Astronomy Boy site. Very common practice nowadays.

All in all, the CR-150 HD is a good refractor of that aperture. With the availability of getting a chrommacor adapter (a little pricey at about $500-$700) you can darn near make it into an APO. I have seen these adapters on 4" refractors and was very impressed. The regular CR-150 will exhibit false color; usually a yellow to purple halos or rings on the outlines of the moon and planets, especially Saturn and Jupiter. As for deep sky stuff, that problem isn't too noticable. This scope also brings clusters in very, very well. When I had mine at a dark site, globular clusters like M13, M92, M5 and even M3 were great views through the eyepiece. If you get this scope, a few changes...

Replace the diagonal prism with a good star diagonal, mine was a Tele_Vue. The 9x50 finder scope is nice, but I put a Telrad on mine to save a little weight. Some folks opt for a right angle viewer. That's OK too.

There is a CR-150 (or large refractor mail/news group) at Yahoo EGroups. Just go to Astronomy/telescopes and get on the list. Tons of info there. Good Luck!!