I'm new to BDO, and I'm mainly here for the PVP. As I'm new, right now I'm not concerned about high-level PVP, but just the average experience. 

Two questions

I wanted to try playing with a PS5 controller. My experience is that generally the mouse/keyboard is god-tier relative to using a controller, how is it in BDO? If two players of "equal skill" faced each other, one with controller and the other mouse and keyboard, how competitive would it be?

Second question. Should I factor in my intention to play with a controller when picking a class? If the answer is yes, which classes are good choices? Which should I avoid? 

Thx in advance for any advice. I'm not worried about being optimal, I'd just like to know what to expect and to avoid any regrets. 

Play Strooker or Mystake. Those are some of the best picks for a controller to play like a master.

I used to play on Xbox for a few years and I switched over to PC about 4-5 months ago. I don't really do much PvP these days although I did enjoy it in the past. As far as playing with a controller is concerned it works very well due to the nature of the games combat system. I would not recommend using a standard PS5/Xbox controller though because there's too many combinations that require multiple key presses with the bumper buttons and main triggers. You really need a controller with back paddles that you can remap every key and save profiles for each class you play. Xbox elite controller works very well although you need to use the Xbox to remap keys and save the profiles on the controller. An example for this would be my Zerk having remapped keys on the back paddles for right bumper and B and then remap the bumpers assigned to left bumper & Y. You can effectively remap your buttons to suit your play style to whatever feels the most natural when you chain abilities and combinations together. The idea is to set up your gamepad so that you very rarely take your thumbs off the movement sticks.

One thing to be aware of is that Rabam skills are gimped on controller and you can only assigned them to the dpad. There's no key combo for them. They also have a delay when using them as a single action which is very annoying. A workaround is to use them after certain abilities, but it's nowhere near as good as using a mouse and keyboard to activate the commands.

You can pretty much play any class when you have the ability to remap your keys. Striker & Guardian work very well and Succ Zerk is pretty good also apart from the one annoying Rabam skill that doesn't work properly. 

You will be at a disadvantage to M&K players, but it's definitely a much more chill way to play the game and you can get fairly good on a controller.