I like the Silhouette better than the O'Day--just in terms of the solidity of the boat. As others have pointed out, if you just want to go a little bigger, there are plenty of great 22's out there. I see the Catalina's everywhere, and they seem to get sailed a lot. I guess that is my reason for the preference. The O'Days that I see are rarely off their moorings. So the truth is I have no great reason for my preference other than, when I was looking for a boat, I didn't think the O'Days were as well built or designed as the other boats I looked at.
I looked at a LOT of boats.
I also agree with the folks who said "get a boat and sail for a while." If you use CL as your broker you will probably get about the same $$$ back as you put in to purchase it. I bought a 16' day sailer (AMF Sundbird) and we sailed that happily for two years. Then I heard a lot of complaints about tippiness and "facilities" and I purchased a considerably bigger boat. Turns out that I LOVED both boats and my family was unimpressed either way. Sail and see what happens for short money would be my advice!
1967 Soverel 28
He not busy being born is busy dying