I've heard that before, obviously he's not as good as Koevermans. But in comparison to Ryan Johnson, he is way better at holding up the ball. Keeping Santos in the middle allows you to put RJ out wide in the 4-3-3 where he's more effective.
I'd still take RJ over Gordon. He has a platform to score in SJ on perhaps the best team in the league, doesn't mean that's sustainable in the long run or that it'd work for TFC. He also seemed to be less than a 100% fan of Aron Winter, so I think it's almost a moot point. RJ was happy to come here, Gordon was happy to leave.
As for Avila, I think he's better than who we start on a regular basis these days, but otherwise his impact on the field leaves much to be desired IMO. Both Santos and Avila are backups on a good team because neither in terribly consistent. I like Santos more personally, but at the same time I think the difference (impact wise) on a team is comparable between the two.