I think the top companies change every quarter, even though the changes are not major.
In my opinion nearshore is better than offshore if you have to choose between the two.
You can find reliable ratings for the top software development companies on platforms like Clutch, GoodFirms, and G2. For a more in-depth look at some reputable software development firms, check out this guide on companies in Bristol: https://www.cleveroad.com/blog/software-development-companies-bristol/.