I think you haven't gotten any replies, still, because no one has any good info for you. I, for one, know nothing about your price point.

Do you really mean "smoke"? Vegetarian cooking shouldn't produce smoke, and if it does your heat is probably too high. But maybe you just meant what is more stuffily called "cooking effluent".

OTR microwaves don't hardly do anything at all, so I would hope that your new hood, just by having a better fan at least, would do better than that. Even 600 cfm, however, isn't so all fired sucky that it'll pull outside of its catch area. It is a perfectly adequate power rating, however, unless you have a really long duct and/or a bunch of twists and turns in it.

The rule of thumb is that your hood surround should extend beyond your cooktop at least three inches in each direction (not including wall). If you look at the filters underneath, you'll see that they probably aren't as big as the cooking area. The plump of steam, et al., extends up from the pan in a cone shape, so moves out as well as up. That means that having the extra inches helps the hood get at the stuff that's going up. Otherwise, the fan has to pull it back as well as up, which takes more power and is less efficient.

I don't know which would be best. Maybe repost asking which is better, larger catch area or bigger fan. That might get more attention.