I've tried a few different ones in the past - wood-based, fuller's earth (cheap and not so), catsan. The only one the cats all seem to mostly like is Bio-Catolet - the boys love it and Charley uses it too. But she pees on the side too. I put an extra tray in the kitchen (we haven't got room for 4 trays, but we've now got 2) and I've taken the flap out for her, but she still wasn't using it until I replaced the litter with paper.
Charley normally pees more like a dog anyway, in that she doesn't dig a hole first or try and bury it; she just pees on the grass if it's fairly dry out. It's only when the weather's bad or cold that I have to put trays down..
She's also been known to precision pee in the wok, bowls, and at the weekend in a small tray that had had two courgettes in...maybe when we get the downstairs loo fixed we can train her to use that...