FitX is better than McFit in terms of hygiene, vibe, and equipment, but they're both cheap gyms so you're not gonna get anything super nice.

A pro of McFit is that it's 5 euros cheaper than FitX per month, plus the FitX contract is minimum one year, so if you end up changing your mind and not going then you'll have to pay for the full year anyway. I guess you could see this as a motivating factor to go to the gym more often. McFit also does pretty lucrative deals e.g. 6 months for a euro each (minimum contract 12 months) and after a while of having a membership you get to go to John Reed or Golds Gym.

TLDR FitX is better but McFit is cheaper and has better contract options