I love my 4K TV. I buy TV and keep it until it die. I bought 1080p plasma when there weren’t any 1080p content and after a couple of years, content came when there are enough 1080p TV around. I think the same thing would happen with 4k content. Give it a year or two.
As to to benefits of 4K, I see a big difference. Even with 1080p content, there’s a big difference between my 65″ 4k tv vs my 50″ 1080p TV. The image just look sharper. Once 4K content come, it would look even sharper than the up-convert 1080p content.
Since I buy my TV for life, I want to be able to future proof myself. It worked out well for me when I bought my 1080p TV, so I don’t regret shelling out a little more for my 4K TV.