I can start planting my root vegetables (carrots and beets) as early as the end of April. Without the greenhouse I'd have to wait until mid June to start planting.
For me, it's how super sturdy it is. For my wife, it's how many extra amenities we have been able to add to the greenhouse, to allow for lots of customize growing options.
I have a feeling that it may be time to think about another one or adding to the current one that we have. The ability to extend my current greenhouse was a definite selling point with Planta!