Generally < 1 is low, between 1 and 3 is in the middle ground, and > 3 is high. However, that all depends on margins, which is why people generally use P/E or forward P/E rather than P/S to compare multiples. Issue here being that P/E is nonsensical for unprofitable companies or companies with very low margins. Spacex's P/E after Google pushed them into profitability by a slim margin would look absolutely stupid.

I would also like to point out, that on a forward P/E basis, AAPL is quite overvalued compared to historical norms, but basically every tech company is right now.