Surprised no replies yet. Don't let the 88s fool ya, they can be a big money pit with age and hours too. But I feel as long as the electrical is good the 88s will always be worth fixing, pretty much no matter the cost. Advantage with the 88s is you can pretty much fix anything on them in your shop or in the field with a few wrenches. They do have lots of belts/bearings/auger bed/etc but everything is easily fixable with a little common sense.
70/8010s I have no experience with other than a spectator. It will be interesting to see how they pan out with high hours. Even moreso than the 88s, the death of them will be electronics. But mechanically I think they have the potential to hold up well. Lots less moving parts than an 88. No auger bed. No feeder belts. The problem areas will be where grain flows (augers, grain troughs, grain tank, unload).
I see advantages and disadvantages to each platform of machine, its just gonna be whatever floats your boat.