Hi Guys,
thanks for all the great feedback. I have now done three dives in the new Mares fins. I have found the buckles relatively easy to flip open when using gloves in the water. However I do find I need to open both sides to get them off which is a bit of a nuisance.
As for the lengthening of the straps I am still having trouble getting the strap to feed readily unless I make sure the angle is right. Basically the rubber ridges on the strap are quite high and get caught on the leading edge of the clip. I can't imagine this will get easier with wear since it is an issue of the ridges getting caught and that shouldn't change over time. Interestingly this seems worse on the Volos that I got and not so much of an issue on the Avanti X3's that I got as a spare pair. Don't know why that would be since both fins use the same buckles. My old fins used the same type of system and I never had any problems with them, so it is not a matter of user error. Anyway this is not that big an issue. It is not as if it is something that I have to do quickly and efficiently in an emergency situation, so it remains just a minor inconvenience.
The fins are nice to use. I can't say I have noticed a huge improvement in speed or effort compared to my old TUSA's but there is a significant improvement in manouverability. Also get good propulsion with frog kick which was pitifully slow in my old fins.
The fact that these fins are 200g lighter than my old ones will be a bonus for travelling.
Overall I am pleased with them. But I still may consider some spring straps in the not too distant future!
Thanks again for the advice, Dave