Right at this moment when BTC is at all time high and altcoins are on red, I'm going all for alts. It's the best time to buy the highest amount of alts for the littlest amount of btc/fiat, if there are projects you believe in.
It's not like that. Bitcoin is all time high because people have invested into bitcoin as the fork is going to happen on 25th which will give chance to people to earn equivalent amount of bitcoin gold which will be another alt and in simple way it's going to be all time high alt aftwards. This is same case as bitcoin cash where people earned couple of thousand dollars by doing nothing. Literally nothing. That's why people are more into bitcoin for now and soon everything will reset after fork goes off smoothly.