Gawd, it's all ups and downs, innit.
When I started Roundup out, I told Ka-Ping Yee (the author of the original design) about it and he said words to the effect of "woohoo!" - I've since lost the email though, which is a shame.
Roundup's been in development a long time, and many a good and bad idea have been tried and hopefully in the case of the bad, discarded. It's been fun, mostly, and I've had a relatively loyal following of users who are willing to put up with the changes in templating, tracker configuration, etc.
I even get some words of encouragement - sometimes from people I admire - and that's something that really helps keep me motivated. As one of these people observed, because it's an open-source project, there's often no reason for users to feed back to the author(s) when things are going well, just when they're going wrong. Most of the feedback is embedded in message of thanks after I help users out with a particular problem (a sample of these may be found on the Roundup website)
Then, there's the occasional ... well, misguided user who just wants to point out all the things that are wrong in your software. Never mind that they've not offered to help remedy any of it. They're just pointing out that your software sucks in this way, this way, this way, and that they're never going to use it.
A pointer for those who approach open-source projects this way: don't tell the author(s) that their software sucks. Take note of the bugs, and file bug reports. Help them build a better piece of software. You're achieving fuckall by just putting them down.
On this point, I just noticed that the Mozilla project has Bugzilla Etiquette which outlines some guidlines and indicates that "...developers are generally a friendly bunch, and will be towards you as long as you follow these guidelines." It covers some of the things I've already said here. At least I'm not alone in all this :)