I have a customer (small medical practice) which currently using 1G Comcast Broadband. Lots of downtime so they are thinking of switching to Crown Castle Fiber.
Got a quote for 100M for about the same cost. Aside from reliability will the speed be sufficient? Any input is appreciated.

Benefits of a MPLS Fiber link is higher quality connection, low latency, low jitter. I had a customer wait months and months for such a connection and refused a Comcast cable modem connection because they believed it wasn't good enough. It all depends on what they need the internet for, right? 100M fiber is going to be good.

Speed should be plenty. Most small offices don't realize just how little bandwidth they need. "The internet is slow" complaints would probably only start to arise if a small office has less than 50 Mbits down or 20 Mbits up in my experience...

Keep in mind Comcast is a shared circuit.
Probably 960 M × 35M. Crown Castle fibor will be
Full 100M X 100M
That should be very good for a small office

So Comcast fiber is shared? I just assumed it would be 100M/100M. Thanks for the info.

If the fiber is on a PON system, it could also be shared. However, the fiber connection will be much better in terms of latency and jitter and free from EM interference that coax cannot match. I would go with the fiber connection and not even think twice about it.

CC Fiber. I work with them. If you need help, let me know.