There are a few things which are better in GH, some are better in GL. Which one is which is really subject to taste (I prefer the review workflow in GL, I much prefer the simplified issues management in GH, but I got the exact opposite opinion from colleagues). GL used to have the upper hand with CI, but lately GH actions again improved enough that I don't mind it.

For a professional setup though, GL CE offers an escape hatch and can be a _huge_ cost saving measure if you ever find yourself needing it. Managing GL in a container is almost painless in the last couple of years. By contract we're actually running on an older GH plan due to plan cost increases we don't find reasonable. On that basis alone, GL seems a no brainer. Both GH and GL online services princing plans can have questionable costs in several scenarios.

GH can give your project wider visibility due to it's popularity, but I never had any any complaint from developers. I see issue reports coming in on GL even on obscure projects, and in most cases devs already have accounts on both platforms.

I do see somewhat less random requests for generic help on GL (as in "what do I need to do to install this?" which is answered in the README), but it's really hard to quantify seriously.