My regular gym was the Rödingsmarkt location, but that one closed for 3 months back in May for…read morerenovation. They're now a month late with no signs of completing soon, so I imagine they're using the same crew that handled the Elbphilharmonie.
Prior to the renovation, the Rödingsmarkt location was just a regular Fitness First, so going to the Europa Passage Platinum Club location should have been a step up. Sure enough, the workout machines are slightly fancier with rep counters and timers, the locker room finishes are higher end, and they have an entirely non-advertised hand/shower towel service (I still have no idea if you have to pay for this given how few people use it). However, it feels a lot like flying Premium Economy on a A380. The finishes are nicer, but you're still stuck in an airplane with 300 other people.
As others have pointed out, the biggest plus to this location is the view. It's on the 3rd floor with sweeping views of Jungfernstieg and the Alster. On a clear/sunny day, it's really awesome.
Otherwise, this location is pretty small overall, especially compared to Rödingsmarkt pre-renovation. I stick to morning hours since it's pretty much unusably cramped later in the day. Even in the morning, there's constant passive aggressiveness racing to get to the machines first but, since it's mostly the same set of folks, we've learned each other's routine as long as no "I'm going to the gym every morning now" person shows up randomly for a day or two.
The biggest downside to this location is that they do the morning classes on Mondays, Wednesdays, and Fridays in the small freestyle training area, which leaves no other area/equipment for everyone else at the gym. They also blast music for those workouts on top of the gym's music, which makes for some really awful layering. Pro tip: with the exception of Tuesdays, you can just go into the group studio to avoid those classes.
The Jungfernstieg U-Bahn, S-Bahn, and bus stops are all close to Europa Passage, so this location is definitely convenient from a public transport point-of-view. It also has a StadtRAD station right in front of it. Pro tip: stick to the main elevators, not the outside glass elevator. That thing is slower than molasses.
All in all, while I'll be gone before they ever finish the renovations, I'd probably go back to Rödingsmarkt over Europa Passage, especially since the former will re-open as a Platinum Club with the same higher-end finishes as the latter but with nearly twice the amount of space.