Bell Fibe can mean different things.
The most reliable is Bell Fibre Optics directly to your home - FTTH. You can tell by having upload speed same or almost the same as download speed e.g. 3Gbps download, 3Gbps upload; 500Mbps download 500Mbps upload. Some Bell Fibe are FTTN (fibre optics going to a central node and not to your home directly), and it will only give you much slower upload speed as compared with download. FTTN is not much better than Rogers.
You can get good deals as a new customers, but usually for 2 years, and the price would go up.
But in terms of reliability, there is no comparison. Bell FTTH simply works, and you can expect NO downtime at all. It's a revelation after you are used to Rogers going down every now and then for no reason.