And the SD devices will A) last forever B) retain value for a long time. A 702 is about 3X the price of a F4. In terms of features the F4 wins, tracks, TC, etc. But you could probably drive a car over the SD box and have it survive and that is not going to happen with the F4. The F4 will probably not be worth +50% of what you paid for it in ten years and the SD probably will.
My Sound Devices 552 was purchased only 6 years after it was announced, and I paid much much less than 50% for it! Shockingly less.
The Zoom F4 will undoubtedly for sure lose less value (as even if it loses 100%, it still has lost less dollars than the 552 did for the seller!).
BUT that formulas if very personal, and has many years of experience behind it. If I was new I would probably lean to the 702 because I probably can't break it and I wouldn't know the demands of what I would be doing yet. I suspect that if I were doing a lot of run and gun or doc work I would lean to the 702 because of durability and ease of service. The F4 in that case I would be leery of the lack of track record. It could be a rock, but it hasn't been out long enough for anyone to know.
The F4/F8 has been out long enough, and has so many users, that you can have similar confidence in it as you would in Sound Devices gear too.