I'm going to stick my neck out and said I've long been a Dyche fan. He can organize a side, gets them to work hard, and has had results with inferior caliber players.
Will this translate to success at Everton? I don't know. He'll have to play less defensive football here, create a more attacking side, show aptitude in buying higher value players, and set out the team to at least have a chance to win every match. Who knows what ideas he'll have or what he's capable of doing with a better caliber of player. Whenever managers take a step up, it produces varied results, but I would argue the same for managers stepping down (Could Ancelotti manage our side? Much easier to set up Lewandowski, Robben, Ribery)
Poch has been very successful in transitioning from Southampton to Spurs, Brendan Rodgers was mixed results at Liverpool, Moyes was a success then stagnation here, Martinez was a quick success turned calamity here. There are no guarantees, but there aren't guarantees with appointing Unsworth, a man with zero senior management experience, or a foreign manager with zero PL experience, or a manager who hasn't managed any club but a superclub before.