The current popularity of Reuben here, is not a reflection of the name's popularity here in the States, as a couple of people have suggested.
The opposite is true.
Ruben is the more used spelling over here, reflecting the Hispanic population, and while that had a steady spelling of being in the mid to late 100-and-somethings during the 70's, 80's and most of the 90's, it is now on the decline. It was ranked #371 in 2015. Ruben has never entered the Top 100 or Top 150 in the States.
Reuben is even lower. Much lower. It was ranked #881 in 2015. It was at its most popular in the 1900's/10's/20's with most of those years spent in the early 200-somethings, it has only spent a handful of years (just) inside the Top 200. The 30's through to the 90's, it was largely found in the middle of the Top 1000 (the SSA produce a Top 1000 here), ranging from the 300's to the 600's. Since the 90's however, like Ruben, it has been falling further. In 2012 it was almost out the Top 1000 at #972.
Basically, what I'm saying is, during the two decades the name has been soaring in the UK, it has been falling over here in the States.
Whatever the reason for the popularity in the UK, it's nothing to do with the trend over here. Reuben is seen as being Jewish - very Jewish - over here, and I think that's why it hasn't really caught on. Even Nehemiah is far more popular than Reuben.
NB: Love the name though, it's my dad's name. It was ranked #499 here the year he was born. And yes, we're Jewish! 