i ordered my Gen 1 without one and that was the right call as there were a bunch of issues, leaks etc with those roofs. My Gen 2 came with one as I bought it off the lot. Really nice to be able to stick your hand up to make sure that you have clearance in garages. That said, I did have to get it fixed-only non scheduled service on my Gen 2.
My Gen 3 came with one as well. All of that said, you are likely saving yourself a hassle by not having one and don think you will hurt resale.
My Gen 3 came with one as well. All of that said, you are likely saving yourself a hassle by not having one and don think you will hurt resale.