An honest question

I'll be a bit honest. In my country quartz prices are really expensive, and only worth when your purchasing the most expensive pack, so I think not much unless if you really like the servant or has money to spare.

This is basically gambling your money away for a servant you want and I've heard people using 1300 quartz and not getting what they want and the GSSR does give an SSR, but it has an 11.11 % chance for anyone to appear so people jump for it specially for people who don't have a single SSR and is desperate (that happens specially when you're f2p)

So how does it feel? Nothing really. Nothing special, it wasn't as special when you get an SSR after a few tickets or 10 rolls. Though pretty happy I got what I want from the Knights, but other than that nothing making me slightly regretful.
Is it worth it to spend rack ton of money? Yup if there's someone you really like or has money to spare, but honestly I'll stay away from servants I don't really care and use money I saved while making sure I could still live comfortably, but as this is basically gambling no.

If you still want to risk your money and not getting what you want (there isn't a rate up for someone after all) then go. Go for the cavalry for the gameplay purposes or if you just want someone the knights then knights.

Sorry for the long reply....by the way quite amazed you have two. It's already a tiring affair farming for one account after all.

Here's my own experience that is both from the point of view of someone who did NOT have a SINGLE SSR the first time the GSSR banner came around and now, having 7SSR uniques (8SSR total), so it'll be long. TLDR at the bottom if you want.

The First time the Guarenteed Gacha came around, I was indeed starting to get desperate. At the time, the only servants I really had that I were considered "good" were a fresh Heracles and a Cu lancer I gave grails to. Other than that, I had Siegfried and Emiya to carry me throught the story only.

The desperation came after blowing free saint quartz on the first Scathach banner and getting nothing (but Herc). I saw the banner and sat on it until the last few days and rolled. I wanted literally anyone but Jeanne as whenever I used a friend's, it was pretty lackluster compared to using Gilgamesh for example. Lo and behold, I was given Jeanne. It sucked, I was pretty disappointed and did sort of regret pulling. NOW I definitely appreciate her, especially since I've raised some more Art focused servants, but at the time, for the first SSR I wasn't too happy.

Fast forward to today I now have:
Jeanne
Altria (Seiba)
Mordred
Tesla
Jack
Orion (NP2)
Xuanzang

To be honest, I didn't feel like I need another servant. I feel like this group along with my other 4*s and even 3*s I can clear most any content the game throws at me. In particular, the last few events weren't really an issue for me. And yet I still pulled on this banner for the Cavalry. I was hoping to get either a Tamamo or Waver since that would REALLY set me up for the rest of the game but would've been happy with anyone, even a Vlad or Medb (actually do kinda want them). The only ones I would not have wanted would've be Xuanzang or Jack.

I got NP2 Xuanzang. But I'm not really disappointed this time around. In fact, it'll probably work well since I was pleasantly surprised with Xuanzang the first time I got her in her event, and 200% damage on her NP is pretty good. I'm not hurting for money either so that isn't an issue. All in all, I feel it was worth it since I know I'm going to stick around for the long haul.

TLDR: First desperate pull was disappointing but worth it in the end. Second pull wasn't needed but worth it imo since I'm gonna play for a long time.

Hope this helped somehow.

I am an average Master with somewhat above average luck. Having pulled a decent amount of SSRs, I actually think that the 1st and 2nd Guaranteed banners are not worth it for people with an already alright roster. The 3rd one with a banner for each class (with Jeanne bundled with Jack) is the only GSSR I'd be spending again on.

Obviously for Masters who do not have a lot of SSR units from either the Knights or Cavalry classes, the current banner becomes a pretty good deal since the chances of getting someone bad or a dupe is low. However for some people who have a good spread on units, there's really not much incentive in rolling unless you really want a chance at getting X servant. I personally am only in need of gold Casters but 3/10 is too low of a chance for me to want to spend Php 2k.

My first GSSR back in December got me a dupe Artoria. That honestly felt like a waste of money since I feel that getting someone new to raise is better than strengthening a unit I already own.

If you think you can justify throwing cash for a game accompanied by a shiny png of a (possibly new) SSR, then by all means do so. But you also need to balance in the risk of disappointment and regret because in your case there's about a 60% chance of getting something you'd not want. If you don't want any of that, then just skip the banner and wait for the class split GSSR at Thanksgiving. It's probably the best deal in the game unless they do something crazier for JP's 3rd anniversary.

Also, sorry for the wall of text.

Just dropping my 2 cents. Having no 5 star was no issue for me for a 98 day old account. Was saving for summer banner archuria. I had money to spare so bought the 40 dollar pack and got drake. When I rolled I kinda felt hollow lol. Like I sorta cheated but was still happy I guess? Failed on raikou 180 quartz and swore to just roll for 4 stars from now on.

This game helps you cope with great story and welfare monsters like ridertoki and kuro with the prisma causeway coming up. So I honestly wouldnt be mad not getting archuria.

I didn't have a single SSR on a 5-month account at level 117 with my F Luck. So I had nothing to lose when I rolled on the guaranteed gacha and I was rewarded with Cu Alter. =) That was the servant I wanted the most, but I really was just hoping not to get Medb.

To be honest I probably wouldn't have rolled if I already had 7 SSRs as you have. The chance would have been too high to get something I didn't like/want.