Both of those are demanding frames.
The feel fetishists in this forum will tell you to go with the 90 and with good reason. When you absolutely nail the sweet spot, it is glorious. Even more so when it's a cross-court 1hbh winner.
The current 6.1 is a great frame in its own right but plagued by the infamous Wilson QC. The one I ordered was almost perfectly in the spec range I like, yet the frame came out feeling anemic compared to my nCode 6.1 95. Although, it still crushes the ball in a way I think only a 6.1 can.
If I had to choose, I'd take the 6.1 but that's largely due to nostalgia and the affinity that I have developed for the 6.1 95 over the years.