We went the no legs route and have been really happy over the past 3 years. The reason we went with ground level is because of the increased soil volume and water retention benefits that elevated structures don't offer. Of course elevated structures have benefits to. They are easier to move if your veggies aren't getting enough sunlight. They are also are cheaper to fill with a premium grade potting medium and they take up less space and come pre-assembled for easier construction.
Anyway, in the end it's up to you and really it depends on how long you see yourself doing this. All I can add beyond this is some super awesome pics of mine!
This is the front side leading into the beds.
View attachment 63562
Here is a pic of the back. You can tell from the color of the wood that we have added more boxes over the years.
View attachment 63563
Here is a side view with Shelby sniffing some Lemon grass. We also fill pots full of herbs and flowering pollinator plants.
View attachment 63564