I would generally prefer wallets that do that. If a wallet screws up the picking of k (most classically: using the same k, for different messages) it leaks your private key. A wallet that uses a deterministic k is far less likely to screw it up (as it's so much easier to test, and has no dependency on a good random-number-generator).
What I do like about random k's though, is that by generating a different signature every time -- it helps developers realize there's no canonical signature. (although using a deterministic k does generate a canonical signature, it's not possible for someone to verify that it is in fact the canonical one, without leaking the private key)