i would have thought with a 90hp it might be underpowered.

I used to have a similar boat with a 115 and wouldn't have wanted less.

Had a few mates with them and they seemed happy with their boats 

 Same Jackman designed hull as the Genesis I think. Very safe and stable boats but a typically hard ally ride in the chop. Had a Genesis 550 with a 115 4 stroke and power was about right. 90 may be a little underpowered. Had that out in weather I had no right to be in and never felt unsafe. Hours wise 420 is nothing provided it has been serviced regularly. Rule of thumb I was told by the mechanics was 100 hours is about equivelent to 10000 kms on a car.

Went out in it one day down Hamelin in reasonable conditions if not a little bit lumpy and was pretty impressed with the ride and was still dry down the back of the boat. 

Will say check the transom motor mount area for any signs of stress fatigue. We had to nurse it home that day due to noticing a crack there that appeared to flexing when moving. Was an easy weld repair and not too expensive from what I heard but worth checking out. Had a 150 etec on it and seemed well powered.

 if anyone is elling an aluminimum boat between 5m and 6m i would love to know