I have a real restaurant griddle. it's around 3/8" thick, very heavy, 30" wide model. there are 4 distinct burners.
2'x3' is huge, unless you regularly cook for a lunch crowd, it's overkill. in fact, I rarely use mine anymore because it's big and takes so long to heat up and for the most part, a cast iron griddle on the grill serves the purpose much more efficiently.
also keep in mind the upkeep. I do mine the same way we did when I worked in a restaurant. which means it takes longer to properly clean and season than it does to cook a meal unless you want your patio to smell like a greasy diner.
if you don't have a restaurant supply drywall screens are a good substitute for the restaurant versions and peanut oil won't smoke as bad as lard.