Should I watch this ??

It's Paul Thomas Anderson you should watch it just for it been directed by him.

It's his weakest film and it's still a very good film just not up to what came after, I know PTA had problems with the producers and the studio and they recut the film on him. Philip Baker Hall is excellent in it. Samuel L Jackson is great also, shame he hasn't done another PTA film since. John C Reilly is great, and even Gwyneth Paltrow is also very good in it. You see hints of PTA style throughout. Not his best film but definitely you should watch it to see a master film director starting out.

You should make up your own mind instead of asking this on every board.

With that said, yes.

Yes, it is a masterpiece, with an excellent director and a great cast.