I don't know how much help I'll be, but a couple of things....I own a Savage X, BUT just purchased a Revo 3.3. I think there is a perception that the Savages are slow (Traxxas guys usually) and that the Revo is fragile (Savage guys usually)...but that's just human nature at work. Since my experience with nitro's revolves around older Kyosho buggies, and more recently the Savage, I will comment mostly about it.
Service:
I doubt you will be able to compete with HPI from a Customer Service standpoint. They have been nothing short of unbelievable. They have sent me a new spur (even though I did not fry mine like many noobs do), new roto start (yes my roto start went out after about a month). You can always reach a real person every time you call them, and if there is an issue, they will do everything they can to correct it including sending you new
FREE parts. We all hope we don't need to use the warranty for things, but if you do....well HPI is IMO hands-down the best I have come across.
Durability:
Again, discussing the Savage side since I have first hand experience with it, I can say it will take a beating.
I have jumped and bumped things (not quite at Wide Open Throttle--WOT) and I have yet to break anything (that video as it indicates is only of "baby" jumps, but I have taken it off some much larger jumps at our park). With this hobby, it's just a matter of time---you will break something, but the durability of the Savage has been well documented and I can testify to it. To be fair I'm sure you have read that the Revo A-Arms break easily, but I belive some RPM replacements (which BTW carry a lifetime warranty should solve that---~$50/full set).
Performance:
As I said I have the X which has the newer F4.1 with is ported differently than the older .25, and I am pretty impressed with the power this engine produces. I am running a 18/49 CB/spur setup in my X which is on the tall side (on it stock came a 15/49 setup), and I can still pull wheelies pretty much at will.
This video might give you a idea of it (although this won't provide you a good idea of top speed). I agree with you on top speed of the Savage to be about 32-35mph. The Revo should smoke it, but I will also tell you, 32-35 is a lot faster than you think... but I can see you quickly looking for more speed (I'm there now). I will probably be dropping a new engine into my Savage before too long, but the Revo should help fulfill my speed needs too
Other:
I guess at the end of the day it boils down to a couple of things. Where are you going to be driving the truck? I would think the street would favor the Revo especially if you have some long straights so you can see the speed. On the grass, and around the yard, I would doubt one is going to stand out more than the other. One the track---I'll just ignore since you said you would not be racing. When I was in your position, I actually choose the Revo...and then 1 (yes ONE) day later the Revo 3.3 was announced...so I returned it (to wait for the 3.3) and bought the Savage X. I'm completely satisfied with my purchase, but my personality keeps me always wanting more. Now I purchased the Revo 3.3. I will have a back-up MT, and IMO the best of both worlds. Good luck with your decision.
-Jason
Edit: Fixed video links