I've belonged to Main Event on-and-off over the past 10 years since it was called "Evanston Boxing…read moreClub" and was located on the N. Side of Downtown Evanston. The former head coach Dave was a solid trainer, and the current head coach Andrian is no different. tl;dr: it's a great place to train if you care about a good boxing/kickboxing workout with good people.
The gym itself is well-stocked with basic equipment, respectably sized to handle classes of up to 20 people at a time, plenty of heavy bags, and boxing gear available to borrow (jump ropes, gloves, handwraps, focus mitts, although you should ideally get your own at some point if you join). It is extremely bare-bones and low on amenities beyond equipment - there is no shower, no water fountain (water bottles available for purchase), and there's a single half-bath. It is very much geared towards people who want to show up, get in a boxing workout, and leave soon after.
The gym has evening classes five days a week (5:30PM, then 6:30PM) plus morning classes on Tues/Thurs/Sat/Sun. There's Muay Thai/Kickboxing on M/W evenings (soon also Fridays again) Andrian is also broadly available for private lessons at reasonable rates (one-on-one and small-group), and I've had little issue arranging to train on my own the few times I've wanted to go into the gym without class going on. There's also a very active kids boxing program five days a week at 4:30 (I don't know much about this, but it looks like Andrian has 1-2 parents helping corral the 15 kids or so - it's a VERY popular program).
A typical boxing class has a 5-10 minute warmup, alternating rounds of heavy-bag work + conditioning, 2-3 rounds of partner drills (focus mitts or defense drills), more bag work, more conditioning, then cool-down stretches. Andrian is very welcoming of beginners and will spend time working with them during class to help them get the hang of things, and the people in the gym are all very friendly and glad to help as well. Most members are casual athletes there to workout, but there's a small cohort of more serious members who are amateur boxers.
Cost is well under what most other gyms with combat sports would charge. The gym is also decent with COVID protocols (asking people to wear masks, everyone cleans the space after class, open doors), but it's still an indoor workout space with high-intensity activity, so you should still get your COVID vaccine if you haven't already.