I've heard a few Shatner tunes from the 1970s on novelty records- things like Lucy in The Sky With Diamonds, etc. While fun listens, I can't imagine listening to them more than once.
His last album, however, "Has Been" was excellent. Well written, well performed (from what I hear his studio time was kind of a drop in party for lots of big music names) and the songs fit his overwrought style of delivery. Well worth getting. As for the new one, we'll see but I don't think lightning will hit twice.