@ georgeanna- In their early days (20 odd years ago) Megabus had a poor reputation here, largely because they put out on the road anything which had wheels, with predictable results. They would put citybuses on long inter city routes sometimes!
At one stage they even chartered space on normal trains and ran megatrain (not like flixtrain in Europe who run their own dedicated trains).
Now they have tidied up their act and very decent buses and quite unusual cross country routes like this one (which starts in Manchester). All routes are now coach style and with restrooms. Sure breakdowns happen, as in any transit company, but they are swiftly dealt with.
On this and many other services they run double decker coaches normally (most of the seats are upstairs, the restroom is downstairs with a few seats around tables), so you get a view different to on the train or even from driving yourself on the same route.
I use Nat Ex due to getting age related discounts but would not hesitate to use Megabus if it was the right route and time (say on this journey to avoid going via London).
But for you I think it's a great idea to use the Megabus- get on, relax, off at the other end. Zero stress.
On this forum everyone raves about flixbus- personally I have had a couple of bad experiences with them (including one case of driver working hours being clearly broken) so am wary of them. But flixbus are what Megabus used to be- ultra cheap.