Don't be so naive to think the Prem is that far ahead of La Liga, look at this:
Burnley
Stoke
SHA
Wolves
Wigan
Blackburn
Bolton
Hull
Portsmouth
average to poor teams.
I could throw in Sunderland, West Ham and Fulham as average/decent teams. that's 12 teams out of a 20 team league.
The good/very good teams: Man United, Chelsea, Liverpool, Arsenal, Us, Everton, Spurs, Man City.
Now look at Spain,
Poor or average teams:
Xerez
Mallorca
Malaga
Santander
Gijon
Osasuna
Vallodolid
Tenerife
Espanyol
Zaragoza
Almeria
Average/Decent:
Deportivo La Coruna, Getafe, Espanyol
Good/very good teams:
Barca
Real Madrid
Sevilla
Valencia
Villarreal
Atletico Madrid
La Liga has no set in stone top4 as luckily for them they have shared champions lague qualification around among several teams in recent years.
As for Ronaldo vs Messi, you have to ask the question, who brings more to the team?
Ronaldo is more of a goal threat, although Messi is fairly prolific himself, while Messi is more of a team player.
For me I'd choose Messi, although if both of them continue at this level of performance they'll be heading for, well I don't want to say it but, best ever territory.