It's "wee" - so it's minimal. Does a good job for its niche.
Cli chat clients are more flexible, with all the complexity that brings with it - but they're usually robust. Command line graphics don't change much :)
gui ones less so, but learning curve is not as steep. That said Xchat is hard to compare to weechat again, as it's a full fledged gui IRC client, rather than a minimal one. (multi network, multi server, dcc/xdcc and scriptability) and it's robust in its own niche.
Been using irssi for years now, and can't say I know/utilise all it offers, but it's great to log in to my server and screen -x into my irssi session.
Hell even xchat is now hexchat. Weechat seems to be a pretty good client.
The nick list on the side does have its drawbacks when it comes to small screen realestate- but for a newbie (and beyond really. It seems to be very extedable) Friendly client it's impressive.
I had an old java based chat client in mind that I used a long time ago and had a similar name.