Personally, I think a dogface has a lot more personality. My dogface is an absolute blast to watch and has already gotten to know me rather well, and IMO has the personality of a dog! A lionfish would definately be more resistant to stress as they're more hardy than a dogface. But lionfish are slow movers and don't do as much swimming or interaction as the dogface, but a lionfish will still be a lot of fun to watch.
I think it's more of a personal preference, but I think you'd have more fun with a puffer. And people say puffers don't do good with lionfish cuz some puffers are fin nippers and it never turns out well if u nip a lionfishs fins lol. But the general consensus is that dog faces are the more docile of the puffers. And it seems a lot of people house dog faces with lionfish. Just look around on YouTube. I know that just cuz it's on there doesn't make it right for everyone, but it does work out from time to time