TeamLab Borderless and Planets in tokyo
 

We'll be in Tokyo in September. I've read about TeamLab Borderless and Planets and am looking to hear what people think of these. If you've been to either what was your opinion? Is one "better" than the other? What was your timing in terms of when you went so you didn't have to wait in line? It sounds like even with advance purchase tickets there could be long lines. Is that correct? Thanks

I just went to both TeamLab Borderless and Planets. The former is the better of the two, though a bit more expensive. You could spend several hours at TLB, whereas at Planets you'll be through it in 60-90 minutes.
I recommend you try both though. For Planets you are walking through water part of the way - it is interesting to see fish projected into the pool as you walk through it.
For TLB, there are extremely few times you can just "walk right in". I chose my my time at the lowest point I could find - 10AM on a Sunday - actually I got there at 9:30 AM and they let us in early at 9:40. There were only a few other couples there at the time. For about 20 minutes, I had the whole run of the place. But from 10 AM, the flood of people started pouring in. There was one area where I had to wait in line about 40 minutes - you go up some stairs and then sit or lie on a net while the projections run above you. You might go there first, or if you don't want to wait, just skip it.
Some areas have mirrored floors - for women, I don't recommend wearing a skirt, particularly a short one.
For TLP, you go through barefoot and you can wear shorts or they have free shorts you can use from them.