Hi, short answer: ubiqpool.io is in fact (date of post) the largest with 49,5% of the whole ubiq cake.

I think you´re seeking for something like this: http://www.ubiq.cc/ or this http://www.ubiq.cc/networkpools

Besides, meanwhile i do recommend supporting smaller pools (some of them have lower or no fees at all)
Half of the cake in just "one Hand aka pool" seems to be against the non centralized thoughts for me.

I was using ubiqpool.io the first weeks too, but then they started having issues. Right now i´m at ubiq.minerpool.net (4,5%) since a week and pretty happy with it.
At the very end you will get roundabout the same results during longrun comparsion regardsless of you´re mining for a smaller or the biggest pool.