Done right the ported 760's can deliver some great power, the problem is, most aren't done right or not matched up to the right components so there's lots of bad press on them. I have a 62T 760 cylinder race ported by TLR ( Todd Lachance Racing) and I love the power from it. It is more torquey than revvy and has a long smooth powerband that just keeps pulling right off idle all the way to the top. Great power for surf riding as it always seems to be in the power at any rev and is smooth and predictable. Tons of power, just not on/off like the 61x can be.
I run an X-scream SS865 in the surf now and have no problem dropping back onto the 760 for a day. The power curve on the 760 is similar in how linear it is, just not as powerful.
That being said, if you do mostly flatwater and want that tear your arms out of the sockets power then you may want to start with the 61x based setup. They can produce violent hp for less money usually and are the most common configuration, therefore the most parts are available and at better prices.
Your electrics will swap right over with no problems as long as you swap all the components including stator, flywheel and ebox.