Concerning crit arts and crit buster

Okay, a little about crit teams: artsmeta and bustermeta characters usually do not generate large amount of stars. There are exceptions like Saberlot and Minamoto but that's exactly why they are a good servants.

Good arts-crit team would look like this:
Saberlot (generator/user) - Tamamo (arts support) - and 3rd arts servant with good skills for crits or high amount of quick cards. It can be:
Fionn (team critgen buff), Orion (2 quick cards for chains and crit damage buff), Nursery Rhyme (crit damage and absorption skill), Archerthuria and so on.

As for buster team... well, just take Zhuge Liang or Hans for crit damage buff, star genarator or/and star user. A good members will be:
Minamoto, Gilgamesh, Tamamo Lancer, Lancelot (berserker) and so on. And don't be fooled by "Intuition" skill on Arthurias - it's not make them crit characters!

It depends on the team you are using and the skill kits. If the servant you are using as your Crit Damage dealer has high hit counts on his buster cards and his skills boost buster damage, then Buster Crit will be the viable option. Also, someone like Ruler Martha has 3 Buster cards not counting her NP, so that’s her focus.

Your best Crit Damage dealer is definitely Saberlot. When all his skills are activated he can pretty much gather, absorb and make good use of stars all on his own. But you also have quite a few good crit servants. Hans would be your main support as he can boost the teams attack and crits. He would work great with Drake, Kintoki or Shuten. A max lvl Shuten can hit for over 40k on her Buster alone when it crits.

The key is making sure you are generating enough stars and that you don’t have 2 servants competing for the stars. So you want your predominant damage dealer to have a much higher absorption rate than the rest of the party. Then eventually wait for Merlin to release like everyone else is and then you won’t even have to try to crit lol

In general crit buster is considered stronger since buster cards have a higher base damage which means a higher crit multiplier and of course they have merlin, Tamamo is as close to a arts merlin as far as supports go, but she doesn't have a critical damage increase like both merlin and skadi on her fox's wedding.

For an arts crit team you already have two of the best servants tamamo and lancelot(Saber), now for the third teamate it depends on how high your lancelot's 3rd skill is and if you have a 20/30 to throw on tamamo if you can generate stars fine then I would go with waver since he can both help with lancelot's np gain and his critical damage buff is higher than hans, if you can't generate enough stars then go for hans and level up his 3rd skill. As for craft essence's ideally run a 20/30 on tamamo, another ending on lancelot for the critical and arts buff, and just look for a waver with 20/30 or if you need hans 3rd skill either k-scope for his np or another 20/30. Tamamo/Lancelot/(support) waver or hans for more stars.

Crit buster- In this team archetype there's very few servants that can fit into it, but the ones that do can make this one of the strongest in the game. Ok you don't have too many servants that can reliably fit into this team, but i'll try my best, so first off hans in gonna be a must since you're gonna need a star generator and you don't want to use quick servants since that can make you have less art and buster chains. For the attacker you can use Drake since she is a rider and on a turn where you have 2 of her buster cards you can use her 3rd skill for stars on demand. Now I would just a support waver since you're gonna need a crit damage increase buff. Now for craft essneces just use 20/30 on hans, victor of the moon on drake, and look for another 20/30 on a support waver. Hans/Drake/(support)Waver.

Right now it could be said to be about even with crit arts being slightly stronger due to a large number of dps that fit that meta and the availability of all three supports that best suit it. But when memelin comes out it's gonna be a wash. His skillset and np help crit buster teams that much

https://www.google.com/amp/s/amp.reddit.com/r/grandorder/comments/7o868w/the_comprehensive_guide_to_team_compositions/?source=images

For these teams, passive stargen and a starabsorbtion skills are crucial as you dont want to generate skills by cards if possible and you need tobwork with limited stars unlesss you have mozart giving 50 stars.

I'd say it depends on the challenge. Buster is pretty straightforward. You crit things hard, they die.

Arts comes with more utility. CD reduction, np drain, skill seal, defense down stacking.

My rule of thumb, if it's a zerk or I have class advantage I go with buster. If its something with np spam I go with arts