I have inov8's, several different pairs. Yes, the inov8s usually use a softer rubber that tends to wear. I don't think you'll run into the same durability questions with these shoes. They don't really have nobs, I don't even know what I would call the bottoms.
I run 80% of my runs on Michigan trails. Which means that I don't have to deal with a lot of rocky hard terrain. I mostly deal with dirt, swamps, roots and occasional rocks.
I've found the inov8's to be fairly clunky. I run a good portion of my miles in old NB900's (I rotate 3 different pairs and each has over 1000 miles on them). For faster days, I'm usually in either Eikeden/Spectrum plus or AdiZeros.
This 790 seems to be a pretty good middle ground between the flats and trainers that I normally run in. I rarely run in the inov8's. I need very slippery terrain to make up for the clunkiness of the shoe.
I am not a very fast runner, my best race ever was probably a 59 minute 10 miler. I run about 2000 miles a year and I haven't missed more than a day or two of training in as long as I can remember.
As for whether or not I would recommend that you run on asphalt in these shoes. Hmmm, good question. Depends on who you are. If you can run in flats, by all means. If you struggle in DS trainers, maybe this isn't the first shoe I would grab.
For those of you running in minimalist shoes right now, this is a pretty amazing shoe. I want to make sure that people know about it. We missed the boat on the NB900's and they moved away from what was so great with that shoe (low heel to forefoot ratio) when they transitioned to the 901 and now 902.
The uppers on the 790s seem much more durable than most of my other flats and some of my trainers. I doubt you'd blow through it very easily. Then again, you may run through jagged rocks all day in the middle of the desert. At which time I'd have to say that your mileage may very.
Love to hear if anyone else has run in these shoes.