Is the GSSR right now good enough ?

If there's ever a time to actually pay for Quartz, then it's the GSSR. 5*s are rare enough that I've seen players go for months before they get a single 5*. So if you really want one, or need one, then I say go for it.

Another good reason to go for this one is that you get to choose the Servant class you want. Unless I'm mistaken, the next GSSR features ALL the non-limited Servants in one banner, so chances of getting one servant in perticular, or even one class, is much lower.

The next GSSR is better as it will feature all limited SSRs ever released so i'd wait for that if i were you.

Not saying that story servants are bad of course, in the end it depends on you, How many servants in that banner do you already have?

Yes, it's worth. You have several months to save up for the next one.

Yes its worth using it unless you wanna sit on it.