Problem as I see it Jim is this, even if it's 100% harmless, there is always an air of doubt about it, simply because someone else before them has done something similar and hammered the users. People's perception of this kind of stuff is usually negative, that's because they install toolbars by the dozen, annoying popups, other bits and pieces that nobody even wants, and other garbage. Now that's obviously not to say OpenCandy is anything like that, and from my own experiences and your description is would certainly appear not to be the case, however anything that can be installed on the sly (even with a disclaimer but without an opt out) is, in my opinion, not on.
In an ideal world, addon software would be opt-in, that is we would be asked if we wanted to install it with the default option being NOT to install meaning it wouldn't be installed if we missed that option and just pressed 'next', 'next', 'next'. We know this will never happen because simply put there is too much money involved. Everytime someone installs something like OpenCandy there is money to be made from recommendations, referrals and other options - when this happens the person who agreed to bundle OpenCandy will no doubt receive some commission from this and so on and so on. Money talks and makes people do things they wouldn't normally do like agree to bundle stuff with their otherwise fine product. Trouble is, if this third party (the "adware") decides to go nuts and sell everything down the river, the developers reputation goes with it!.
Personally speaking, and as the owner of FreewareBB, users have to put up with enough surprises these days, without software developers including all manner of useless addon software in their installers which is nothing at all to do with the software itself, but more to do with making money.
Of course no-one objects to anyone making a little extra cash, but I really do think it does nothing for the developers reputation when they include certain third party addons.
Talking specifically now about OpenCandy, checking WOT
the first thing I see is the reputable "hpHosts" noting that OpenCandy is "Engaged in the distribution of malware". Now this is most certainly not something I would want my software to be associated with, no matter what the interpretation is of "adware" or anything close to it, people see this and run a mile and therefore it's no surprise that FreewareBB have removed software containing things like this. Reading on in WOT there appears to be more than one complaint about OpenCandy although I would be inclined to trust the comments of hpHosts as do WOT. At the end of the day, it really is about individual choices, do you take the chance or not? Is the software really of that much importance to you that you would take a risk? Isn't there an alternative that doesn't include a third party addon?.
I have no stats or information available to determine whether OpenCandy recommends and installs freeware, shareware, trialware or whatever so I'm further limited to guessing it's possibly a combination of them all which, as a freeware enthusiast, makes that particular add-on even more irrelevant to us all here.