Great tip! Thanks. the dual-core w/ 1.4GHz is exactly what I was hoping for at a decent price point.
No, the value right now is the Asus RT-AC1900P (a Best Buy exclusive right now). It is the latest and more powerful version of the 4 year old RT-AC68U with a 75% faster 1.4GHz processor and other upgrades too. Still has the same ram and NVRAM as the original 'AC68U, but for VPN, those faster processors are worth any premiums the RT-AC1900P may have.
In actuality though, the price is the same or lower than the original RT-AC68U. And, it still can use RMerlin's firmware too (just use the RT-AC68U firmware on it).
The RT-AC87U should not be on your shortlist if you want a stress free time with your new router (do a search, many are still having insurmountable issues with them).