I've not used that one but I think they have a good reputation. Generally speaking the Nikon AIS wide angles are far better regarded than the later AFD auto focus versions. That said, they're still usually a bit soft in the corners wide open (maybe not on a crop though?) but like you I've only ever really used them for landscapes where that never really becomes an issue.
As for alternatives, I guess it depends what you're thinking of spending. I had a 20mm 2.8 afd and a 28mm afd. I wouldn't particularly recommend either but the 20mm in particular seems way over valued these days in relation to it's performance. The 28mm can be picked for less than £100 and though it's not amazing, it is good value.
I also had a Voigtlander 20mm 3.5 which is a lovely little lens and I'd highly recommend it but not easy to find for a good price. Just sold mine recently. At the time I bought it, a few people on here mentioned how well the olympus 21mm lenses work with an adaptor. They sound like they're worth looking out for but I've never seen a cheap one.
And one last one, I've just bought a 20mm F4 AIS. It's not arrived yet but when it does, I'll let you know how I get on. That and the 3.5 version both seem to have a stellar reputation.