Tabletop space is important when choosing, but I think there is another important characteristic to look for, and that is leg room. Many desks, like mine, have huge real estate, but the leg room is quite limited. It is an L shape, and has drawers on the bottom sides, and so I can only really fit my chair and sit in the right angle. This means I can't slide around and use equipment or work in the other two sides. Good for storage, but it's annoying in terms of flexibility.
You should also look for a sturdy desk. I think you should be able to jump on top of it and not be afraid of it breaking and you going to the hospital for a broken neck. There is nothing worse than a wobbly desk. Not only can it break when you put your heavy $30k scope on it, but it can also fall and squish your chihuahua!
Obviously you can't have maximum stability while having unlimited leg room, but a balance of the two will make you happy. As for specific models, I have no idea. Check the big box stores like Costco or Ikea if you got one around.