The factory spray in liners are probably the best option. I have that in my F150 and it's great. That said, all the options will work. I have a rubber mat simply because it's easier on the knees and eliminates the corrugations. On a previous truck I had a drop in plastic liner and, while it also needed a mat to keep things from sliding around, I had that truck over 10 years and the liner was fine and no water under the liner issues. If you are on a budget, don't discount the do it yourself roll-on brush-on option. Go with the premium product (Herculiner) and the results are very similar to a factory spray on. I've used it also and liked the results.