I can't at the top of my head remember all the minor annoyances I ran into when I tried Halloy, but things like not being able to paste a large message because "it exceeds the single message limit" was a real dealbreaker.
I ended up going for Crossover and mIRC
Please file bug reports or feature requests when you find them, if they haven't been filed already. Don't just leave silently. And not just for halloy, but for all FOSS projects in general. The developers/maintainers can choose what to do with them - but they'll at least be aware of the pain points. That too is a contribution to the projects that we use for free.
PS: This assumes that you haven't done so. But even if you did, please leave it as a request to everyone else.