I have the go 151 for two months, my wife and kids (8y,6y,5y) use it with low winds with a 2,5m rig indeed with less square meters is will drift and delivers no power to go straight even with the large fin in the middle.
I use a 9.0m and 7.5m SCS freerace sail on it, manage to gain a speed of 49km with 5Bft wind. I understood it can go faster, have to try it. I am no looking for a Ultrasonic 147 for low winds and a RRD Firerace 122 for more winds starting from 5 Bft.
Its is a good start for the whole family and dad can enjoy also as a freerider.