The flutter problem was confined to the original Sceadu; it hasn't been an issue with the Evo. However, you still want the best servo you can get on collective, as it has the highest loads and is worked the hardest in "normal" flying. The tail servo is equally important if you're going going to be thrashing around doing 3D, as are the cyclic servos. There is no real "most important" servo in a helicopter; if any one of them fails you're coming down RIGHT NOW. A tail rotor or throttle servo failure is survivable; a cyclic or collective servo failure, 99% of the time, is not.

Having said that, you will find that putting a digital on collective makes a huge difference in the way it feels. Much smoother and more precise; your hovering will improve drastically. I have a 9252 on my Evo 50's collective; I have good analogs everywhere else. I do have all-digitals on my X-Cell, but just cannot see putting them all around on a plastic helicopter.

Regarding the tail servo; you will be told that one MUST have a fast digital, etc., etc. Nonsense. If you're an accomplished flip-flopper (3D), then yes, you'll need one. If you're learning, or just flying around, a good analog will do just fine. My Evo has a 9402 hooked to the 401 gyro, and I have all the tail authority I can stand.

Digital servos do indeed perform better, due to their zero dead band and near-perfect centering. That comes at a price; higher cost and heavier battery drain. My advice for a novice with a plastic 30 machine is to use standard servos until one becomes accomplished at flying around and is ready to try aerobatics. Then is the time to upgrade servos and battery pack. If you want to spend the bucks on all digitals, by all means go for it. You will certainly be able to tell the difference in performance. But, if I was just flying around and doing mild aerobatics (which is the way I fly), and this was my "beater" machine (which the Evo is), I would put a digital on collective for the enhanced performance there and save my bucks by using good analogs everywhere else. The Evo flies very well on good analog servos, especially the 50 with its closed-loop collective and cyclics. I think it is the hands-down best ship going in the 30-50 plastic market today.

But you're still talking about a plastic helicopter. There is BUILT-IN slop on plastic helicopters. Unless you need the strength of digitals to withstand the thrashing that hard 3D produces, there simply isn't any sense in putting $500 worth of servos on a $300 machine.

Opinions vary... that's mine.

BTW, the advice to NOT use Futaba 3004 servos on a helicopter is sound, but the reason is because of the indirect drive potentiometer on the 3004; not the output shaft being weak, or whatever. The 3001 is nothing more than an S148 with a bearing on the output shaft; a good, solid bread'n'butter servo, suitable for a plastic 30 helicopter; but NO MORE. If you get an Evo 50, use 9001s at the very least.