We stayed here one night and it was a good experience. In lower season (early April), we paid…read morearound 120€ which is cheaper than most hotels on the actual Mont St. Michel, but close enough to be a 10-15 min bus/shuttle ride, with the stop located right across from the hotel.
Location - I recommend staying close to Mont St. Michel (i.e. one of the hotels located just 10-15 min away from the actual "island") so you can get there early in the morning to avoid the crowds and see the tide changing. It's much cheaper than staying on the actual island which can be double the price. It was super easy to get to the "island" via the shuttle which comes really frequently. There's also a few restaurants close to here (Relais du Roy, next door), and a few places for a quick snack (Brioche Dorée, across the street, right where the big gift shop is). The big gift shop also sells food, water, etc. if you're hungry/thirsty or shampoo, soap, etc.
Breakfast - The breakfast was included in the hotel rate, and was decent but not amazing. I didn't expect anything exceptional - it was a standard continental breakfast (yogurt, bread, croissants, cheese fruit, juice, tea, coffee). There's not really anything served hot, as most everything is cold. They start serving breakfast at 7 am so that you can take the early shuttle if you want.
Room - The room is pretty small, like most European hotels. Its decor was pretty artsy/whimsical. The bathroom was fine too, a bit small but decent. I found the hotel to be clean and fairly new (not super modern and new, but it didn't feel like it was built in the 80s and never touched since then).
Amenities - The WiFi was pretty slow and it was annoying that every 15 minutes or so it would boot you off and you would have to reconnect. We were only here for one night, so it wasn't so terrible, but if you are expecting to have fast/good internet and it's a deal-breaker for you, you may want to stay elsewhere. They don't have standard bath products in the hotel - just a multi-purpose shower gel & shampoo all in one product, so if you want conditioner and separate shampoo, bring your own.
Parking - If you call them ahead of time, they will give you a one-time code to enter the gates into the area (it's a one-time, personal code just for you, so if you want to drive out of the area and then return, you'll have to get a new code from them). We got the code the day before our arrival, and it was 4€ for overnight parking which is pretty reasonable. The parking lot was adjacent to the hotel, so we didn't have to walk far with our bags.
Overall, the location was great and perfect for the one night we wanted to stay here. It was worth paying a little extra for being so close to the shuttle, and I'm glad we didn't stay on the actual island, as we were able to get there super early in the morning anyways, and saved 100€ or so by staying just slightly further away. I would recommend this place if you're looking to stay overnight in the area.