With NVIDIA GTX 1070's; is X17 worth mining?
Yes.
Are there particular algorithms that are better for NVIDIA cards?
Yes.
Please advise?
You should benchmark your exact card(s), as there are variations between manufacturers (eVGA vs. MSI vs. ASUS, etc.), and over/under-clock as appropriate.
Thanks. I did benchmark, they're all EVGA cards. I'm just wondering overall which algorithms are typically better for Nvidia?
Generally speaking, AMD is better at ethash & cryptonight, and Nvidia is better at Lyra and Neoscrypt... but take that with a healthy dose of "your mileage may vary".
Though, if you did benchmark your cards, you should already know that, because the mining software would tell you which algos were better than others. Otherwise,
www.whattomine.com can give you some
guidance, but again, YMMV - don't take the profit #s as absolutes.