If you want to get the most fun out of your day and go smooth and fast I suggest that the Futura's are the answer. These boards are extremely fast. Maybe not as fast as an iSonic on a slalom course, but downwind these boards are almost unbeatable. Control in chop is very good and jibing is easy. With the low OFO and volume in the tail it feels lively and small. Nice feature is the behaviour of the boards if you don't want/dare to take max speed out of it: the board stays in control on the water.
I have had 2 session with my FU 93 and scored avg pr's both times. Max speed went close to 40 Kts with a lot of more potential.
I will surf the FU 93 with 6.2 and 7.0, but I think the FU 101 will also be a very nice board for these sail sizes.
I don't have experiences with the iSonics, but after 5 years of surfing with pure slalom boards my switch to Futura boards gives me much more fun and better speed.
I hope Kevin can confirm my opinion or may add some extra insight.