I went to 3 of the overseas GPs last year in addittion to Belle Vue.
Each has its own pros and cons and difficult to do a true comparison. People will make a value judgement based on what they are looking to get out of it.
I think the SGP seems to be moving to smaller venues, with an inevitable increase in ticket costs.
I'd encourage everyone to try various SGPs, and, if they can, to go to a league match as well if one is on before or after the SGP