I think you'll like the E5SS. I've got quite a lot of flights on my E5's now,.. the SS with 715/115 blades is 9.75 lbs, but that's with a full 12S/4350 pack, not the "half pack" setups many people use for lower headspeeds. It's great at 1250 and really scoots at 1750. No pack change, just flip a switch! My other is using 605's and 105 for the blades, both 4.9 tail ratio. 1250 is my lowest rpm due to weight (collective feel) and tail ratio. It'll probably be just fine at lower revs if you go single pack and get it to a lower weight. As for the 3470's,.. you have to accept responsibility when you use them. They're marketed as car servos not heli servos. With that being said, I have them in both machines and will use them in others in the future. They're really light, and seem to have plenty of speed and torque. I love them. If I ever do a big machine again, they have a bigger brother in the 9470, which has much more torque. One thing to keep an eye on is CG. I'm using 12S/4350 packs that are roughly 20 ounces each, and on the 600 some 6S/5500's that are 27 ounces. both machines require the packs so far forward they're literally touching the canopy. of course I have very light ESC's too, which doesn't help the CG issue. I've drawn out in cad a lengthened battery tray but haven't had it cut yet. Might add that to my winter projects since we can't really fly around here for a few months now.