I've been using the MB protect car seat for around 3 weeks now and I think it is fantastic!
I've been using the capsule with the seat belt installed base and it is incredibly easy to click into and take off the base. My husband finds a lot of baby related gear (buttons on onesies etc) really fiddly but the protect has been very easy to use. The base installs so easily by simply threading the seatbelt through and clipping in place meaning it can quickly be moved from car to car if necessary.
My 3 month old is very comfortable in the seat and is reclined enough to fall asleep without me worrying about her head falling forward. The 5 point harness means she is super secure and I feel reassured that she is nice and safe.
The fabric is very easy to clean (we had a leakage!) and it was very straightforward to take the fabric on and off.
Overall the protect is incredibly easy to use, fantastically safe and secure and offers excellent value for money. I would recommend it 100%!