I think Italy has the worst newly promoted class every year cause we usually end up seeing them  most of them go down the very next season they're promoted.. if not.. just 2 years later. I just think Italy's newly promoted classes are just never ready for Serie A and its challenges on any level, financially, morally, emotionally, or physically. Almost every season we see a team get promoted they go back down within 1 or 2 years of that promotion.. and that ends up in either the club being YO-YO (Siena) or the club collapsing in shambles (Lecce, Messina,Modena,Brescia, Reggina etc.) 

The second worst is probably Holland.. Most clubs that come up just cant compete with the bigger boys at all and just don't have the firepower on any level. we usually see them back down 1 or 2 years later.

3rd worst for me is Germany.. when a club comes up.. they play like total shit and go back down right away.. and it happens every year.. and we usually don't see them re promoted for a while. and there is evidence.. look at the record from the bundesliga's newly promoted for the past 8 years... the newly promoted clubs have an abysmal first year record. and we are about to see it again this year with Greher Furth and maybe Dusseldorf.

France also has a problem with promotion classes because those teams tend to choke aswell.. but not as bad as those above

After that is England.. when you see some poor team relegated from the prem were probably excpecting them to bounce back up right away..... and it never happens.. the club collapses. examples (Portsmouth, Burnley,Blackburn,Birmingham,Middlesbrough,Bolton,Sheffield United, Charlton and so many examples but what makes them different from Italy is that the clubs can bounce back from tough times much faster and atleast don't totally collapse as a club. and when a team is promoted they usually do pretty good for acouple of years for example Norwich city now,wolves had 2 decent premiership seasons before last season, West brom has looked like they are getting out of the YO YO habbit. Wigan has managed to beat the drop every season, Swansea has had 2 great seasons, Newcastle recovered from there relegation and has had 3 decent seasons avoiding the drop. its just when something wacky happens and the club is relegated is when things go extremely awry and start to get gloomy. Most of the time.. its not pretty for relegated Prem clubs, especially ones who had high ambitions.

Equal with England is probably Spain.. usually the same things happen in spain as they do england. we do see alot of quick recoveries but also alot of ugly downfalls too.

So in my opinion, (KEY WORD MY OPINION) Spain(aside from this season) and England have the best promotion class in the top 5 leagues in the world.

In spain we have Betis who took of were they left of when the got promoted 2 seasons ago. not beeing a bottom team despite beeing promoted. I think we will see the same thing with villareal when they go up. they will be a EL contender right away like Betis.. Because when big historical clubs like betis and villareal somehow go down and go up again they will not be a bottom team. they go straight up to where they were before

Also look at Napoli who got promoted pretty recently and where they are season in and out..

You're forgetting a key factor in all of this: "Parachute Payments" for those clubs that are relegated (are often more than most clubs make in a year in a top division outside of England) & Premier League Fund Distributions for those clubs who remain in the PL. In short, those clubs who make it to the prem or have recently been relegated from the prem are more likely to bounce back quicker because they have a HUGE financial advantage over the other leagues you are comparing.

It's also the case that promotion TO the Premier League wins you a much more equitable share of the TV rights than elsewhere. Some people moan about the worldwide TV advantage that the PL enjoys, but within the league itself, the rights are quite evenly distributed compared to some leagues.

It helps, at any rate. 

teams which are relegated from EPL can got some really hard times,  npower Championship isn't that easy even it's just 2nd league.

Portsmouth collapses due to bankruptcy

@Lodatz yeah you are right in EPL they distribute the TV rights fair and square unlike the La LigaBBVA the 2 top teams take majorty of the money

Southampton were good... but other than that everyone else is sh*t :P