I'm a fan of hoop-houses.
Rebar and pvc. Very easy, also it's relatively easy to pull a cover to force-flower your pants. Depending on the crop.
The frost is a tough one, and if not planned for, can be a PITA.
I put extensions on the legs of my previous hoop-house due to the low head-room on the sides.
Taking note of daily wind directions to maximize possible airflow through, helps to prevent some problems.