Being worth it or not is totally up to the price difference. How much you need to invest to go from 1070Ti to RTX2070 will dictate the worthiness of the transaction. In my area an used 1070Ti is half the price of an used RTX2070 while the performance difference is, in the games' current state, 20-30% at most. If you are a ray-tracing enthusiast then 2070 is a must indeed.
Thank you all. Not sure if I'm doing this yet as I need to still determine the cost of a new build. I think the only game that would use the ray trace right now is BF5.
If you can wait for the upcoming "Super" cards there may be a shift in price or a better price/performance. Personally I went from a laptop GTX 1070 to a desktop 2070 and it was a good boost but I kept wanting more so I upgraded to a 2080 but then again I only play 1080@240Hz so it may be different for everyone.
As others said, wait a bit, Navi and the Super cards from Nvidia are around the corner. You can make a decision after they come out. Or get a cheap second hand 1070Ti. Also at what resolution do you game and/or what are your monitor specs.
Thanks everyone! I love this site as its the best informative hardware site I have found. FYI, my monitor is 1080@144hz.