Summon Ticket or 30 Saint Quartz Pull?

Well, first, they're two entirely different resources, so why not use them both?

As for single vs multi-rolls using SQ, the multi-roll guarantees you a 4* or higher card, where 10 single rolls does not. There are several good 4* CEs out there. As for chances to pull an SSR, they appear to be roughly the same, going off the old math I could find on Reddit - 1%. In my experience, I've gotten one SSR Servant from a ticket, but 12 SSR Servants from the 30 SQ spins, so it really just comes down to luck.

If you're looking at math, Not A Whale on youtube made a good video talking about the math behind what's better:

https://youtu.be/SsAXKWOoFfU?t=2m38s

He's got some more in his channel if you feel like digging, but this one is pretty good.

Of course, there's no accounting for luck, so if the gatcha smiles on you when you use summon tickets, why not? But from straight numbers, it's safer to do a 30 quartz pull for the highest chance of getting something good.And like TheBlueMagician said, it's good to do both since they're different resources.