Would this be any good for exploring? Jump points? How does it compare with the 315p, the only explorer in the price range?

Overall, expect a 315p to be better at finding jumppoints. The Reliant is more going to be doing in-system/region sensor scanning, research, and exploration. It could still definitely map a new jump if you find one, but the bigger profile compared to a 315p may lead you to flying into a smaller point than you could fit.