I am late to the party here. When you say all the sets, do you mean the weapon sets or also the 5-piece sets? The latter take a long time to fully complete, as you drop only one weapon from the last boss, but you can farm those on normal of course.
The answer is probably "whatever you're most comfortable playing" and "whatever you do the most damage with". Single target builds tend to be fine, except maybe in the ice stage. You'd have to say ranged classes must be easier, but that's not how I feel. I guess I'm a melee player. Pet sorcs should be easy, maybe one of the easiest ways, but I've never tried that.
Magblade has the self-heals on paper and is ranged, but it always feels less tanky and less easy to get damage out of than my magplar. The latter is decent. If in doubt, wear Hexos Ward and maybe Iceheart along with everyone's favorite solo damage / sustain set, False God's Devotion. Or skip Iceheart for Pale Order and 1x Slimecraw. That's kind of the boilerplate for any magicka build. You can go full crit / full damage, of course, but if you're still learning the arena, the above will be better.
I know exactly where the guy who recommended magden is coming from, but for me it's a horrible class, because of the delayed skills. Cliff Racer has a delay. Deep Fissure has a delay. These delays can get you killed. Maybe not, if you play the class well, you are used to it and you really like it. I don't. There is no execute but the unwieldy bear. It's not a very direct class compared to a nightblade or templar, which are IMO both more straightforward (aside from the Merciless mini-game). The weekly rewards for warden sound very enticing, though.
In terms of melee playstyles, you can't beat a stamina Brawler build. In terms of Brawler builds, you can't beat my tank. I did vMA in 1 hour 10 min on it. The "rotation" is simple, yet it kills everything but bosses quickly. The latter take some time, though IMO not excessively so. You can stand in red. You can ignore half the mechanics, because of how tanky you are and how much self-healing this build has ... and I'm not even using Pale Order. This is what indirectly gains you some time against bosses. When the Dwarven construct in round 4 goes into it's fire AOE phase, you can keep standing under it and keep hitting it, ignoring the fire and the adds. No, I'm not a DK using Corrosive Armor. This is a permanent state of being. When the Wamasu in round 7 generates lightning ground AOE, you can stand in it. Just keep hitting it. When the final boss spams you with ranged stuff, you can largely ignore that. When there's a Daedroth, you don't need to prioritize it. This build is that forgiving, because it was designed as a veteran dungeon solo / carry build and it works. What it's not, of course, is fast. Being faster than 50 minutes in vMA, though, is about knowing all the spawn points, covering them with ground AOEs. You have to use the time while you're waiting for spawns and you have to be a really good DD when it comes to nuking bosses. Anyway, here is my tank build:
https://en.uesp.net/wiki/Special:EsoBuildData?id=421256
First thing to note is that this is an actual tank. It's got taunts. It uses the Tormentor set. It uses the Undaunted taunt. I didn't bother changing that. You can, if you want. Use the 2H execute, for example. I just hit everything with Stampede and Brawler. That's it. The Tormentor set gets you to the resistance cap. It's not just about the taunt. The meditation went largely unused. When you're soloing stuff, it's better to get resources on the move via Dark Deal.
I guess I'm using some fairly exotic gear, so there is that. Been running this for a while. The build is, at this point, highly optimised to balance tankiness, sustain and damage. Markyn is there for the resistances as much as for the damage. Vicious Ophidian is indispensible for crit, damage and sustain. Very high crit for a tank (45%) keeps Crit Surge healing activated. There is method to the madness. The Precise Master's Greatsword is as indispensible as VO, for the AOE damage, but doesn't need to be perfected and doesn't strictly need to be a sword.
Why is this build so hard to kill? Self-healing underneath the Brawler shield. You have 3.7K health regen with potion, which should be Weapon Crit / Health / Stam, Dragonthorn / Mountain Flower / Water Hyacinth. You are at the resistance cap (33K). You constantly heal from Hurricane / Crit Surge. You have a guaranteed crit / heal with the gap closer, which always crits. You have a shield from Brawler every second. You heal from Dark Deal. You take reduced damage from Revealing Flare and from Temporal Guard. You never use your ultimate, thus retaining 1500 health regen from CP permanently. I soloed City of Ash 2 hard mode with this (Skoria) the other day. Yeah, the islands got destroyed. It did not matter, because this build can withstand being bombarded with the lava when the islands disappear.
Some mechanics in vMA will matter, of course. If you get poisoned in round 7, that will probably still kill you. I know the arena well enough to always be near a cleanse pool when it matters, so I haven't tested that. You do need to know mechanics in vMA, but the build should allow you to recover from mistakes like no other.
