I just had a read around and saw that the H110i GT is the Go-To AIO right now, it is the newest, recently recalled hardware from corsair. Considering the H110 had problems the GT fixes those problems and haven't seen many reviews containing any problems with it.
How long have you had the x61?
Does the Corsair 110i GT series have a controller as well? I've seen mixed opinions about the software supplied from the x91 and I've heard that corsair's updated ones are better.
+ I've just seen that NZXT's customer support is terrible... :c