Great location, just above Downtown Crossing T station. Grocery store and CVS just a few feet away. We stayed with our toddler for almost two weeks, and although we encountered some (avoidable) maintenance issues the housing team was always very responsive via text.
Accessibility is a bit complicated (listing should be updated with better details) but it's always possible to ask 101 Arch St security team to be buzzed in, eg if you have a stroller, heavy bags, or wheelchair...
Overall, it was a good solution for us, close to the metro, the park, groceries, although a bit pricey for all the maintenance issues we encountered.