LAST 5 SEASONS
*2006-7 Season - League Tables (top 5 teams)*
La Liga
1. Madrid - 76
2. Barcelona - 76
3. Sevilla - 71
4. Valencia - 66
5. Villareal - 62
*difference between #1 and #5 = 14pts
Premier League
1. Man. U. - 89
2. Chelsea - 83
3. Liverpool - 68
4. Arsenal - 68
5. Spurs - 60
*difference between #1 and #5 = 29pts
*2007-8 Season - League Tables (top 5 teams)*
La Liga
1. Real Madrid - 85
2. Villareal - 77
3. **Barcelona - 67**
4. Atletico - 64
5. Sevilla - 64
*difference between #1 and #5 = 21pts
Premier League
1. Man. Utd. - 87
2. Chelsea - 85
3. Arsenal - 83
4. Liverpool - 76
5. Everton - 65
*difference between #1 and #5 = 22pts
*2008-9 Season - League Tables - (top 5 teams)*
La Liga
1. Barcelona - 87
2. Real Madrid - 78
3. Sevilla - 70
4. Atletico - 67
5. Villareal - 65
*difference between #1 and #5 = 22pts
Premier League
1. Man Utd. - 90
2. Liverpool - 86
3. Chelsea - 83
4. Arsenal - 72
5. Everton - 63
*difference between #1 and #5 = 27pts
*2009-10 Season - League Tables (top 5 teams)*
La Liga
1. Barcelona - 99
2. Real Madrid - 96
3. Valencia - 71
4. Sevilla - 63
5. Mallorca - 62
*difference between #1 and #5 = 37pts
Premier League
1. Chelsea - 86
2. Man. Utd. - 85
3. Arsenal - 75
4. Spurs - 70
5. City - 67
*difference between #1 and #5 = 19pts
*2010-11 Season - League Tables (top 5 teams)*
La Liga
1. Barcelona - 96
2. Real Madrid - 92
3. Valencia - 71
4. Villareal - 62
5. Sevilla - 58
*difference between #1 and #5 = 38pts
Premier League
1. Man. Utd. - 80
2. Chelsea - 71
3. City - 71
4. Arsenal - 68
5. Spurs - 62
*difference between #1 and #5 = 18pts
As you can see, in the past 5 seasons (current state of these teams), the Premier League has had a greater difference between the #1 and the #5 team 3 times, whereas La Liga has only done so twice. The point here is not to say that La Liga is so much more competitive than the PL because of these slightly different numbers. The point of these numbers is to show that petty arguments and reducing players' accomplishments due to the "competitiveness of their leagues" is a moot point. The numbers prove that in terms of winning the league, both leagues come out about the same, both being nearly equally competitive for the top 5 spots.
At the same time, there is no denying the difference in tactical approach and physicality between the two leagues, but calling La Liga a "two horse" race isn't really a valid point, when you also consider that:
Since the '99-00 season:
La Liga - 4 different teams have won the championship
PL - 4 different teams have won the championship
Last 5 years:
PL - 4 times Man United have won it, 1 time Chelsea
La Liga - 3 times Barca, 2 times Madrid