Despite the critics' fervent attacks on Koo (in particular), you just cannot dispute the fact that
Koo Kien Keat/Tan Boon Heong make up the best MD pair in Malaysia
at this moment, and arguably in the past 5 years.
1 Asian Games Individual Event Gold (2006)
1 All-England (2007)
4 Super Series (Malaysia & Denmark 2007, Swiss 2007 & 2009)
1 Super Series Masters (2008)
3 GP Golds (Philippines 2007, Macau 2007 & 2008) --
9 individual titles if you discount the SS Masters.
Fu Haifeng/Cai Yun's achievements:
1 World Championships (2006)
2 All-England (2005 & 2009)
5 Super Series (Singapore, Indonesia, China Masters & French 2007 and Korea 2008)
1 GP Gold (Thailand 2008)
1 6* GP (Hong Kong 2005)
1 5* GP (Chinese-Taipei 2006)
1 4* GP (Macau 2006)
2 3* GP (Swiss 2004, German 2005) --
14 individual GP titles
Of course, besides these individual titles, Fu/Cai also won some invitational tourneys like the Invitational World Cup 2005, Copenhagen Masters 2006, the team events such as Thomas Cup in 2004, 2006, and 2008 + Sudirman Cup in 2005 and 2007.
In the first 2.5 years of their partnerships (2004-mid 2006), Fu/Cai win
only 6 titles (including the cap ayam titles
). Since they won the World Championships in 2006, they started a winning run of 6 titles in 2007 and 2008.
Similarly, if you want to compare that with
Markis Kido/Hendra Setiawan in the first 2.5 years of their partnerships before the WC 2007 (late 2004 to first half of 2007):
0 Super Series
1 Badminton Asia Championships (2005)
3 6* GP (Indonesia 2005, Hong Kong & China 2006)
A mere 4 titles (1 cap ayam), but since the WC victory in 2007, they went on to win:
1 Olympics Gold (2008)
6 Super Series (Hong Kong & China 2007; Malaysia, China Masters, Denmark, and French 2008)
1 GP Gold (Chinese-Taipei 2007) --
12 individual titles.
Even if you discount the "cap ayam" titles won by Koo/Tan in 2007 and 2008, I believe their achievements of 1 AE, 4 SS titles and 1 Asian Games Gold in their first 2.5 years of partnerships
more than match that of 1 AE and 2 equivalent SS titles (Swiss & HKG) won by Fu/Cai and 3 equivalent SS titles (Indonesia, HKG & China) before their respective WC victories in 2006 and 2007
No doubt, Fu/Cai and Kido/Hendra have that WC Gold Medals nicely placed in their cabinets. But, it took Fu/Cai 2 failed attempts (2003 & 2005) and Kido/Hendra 1 failed attempt (2006).
Even Lin Dan only managed to win the WC in his 3rd attempts too (failed in 2003, 2005).
Koo/Tan had their solitary chance in 2007 and failed big time in front of the home crowd. Naturally, they get condemned big time and critics had their field day. They managed to partially reedem themselves by winning the "cap ayam" Macau GP Gold (
despite beating the newly crowned World Champions Kido/Hendra in the SF, and also with Fu/Cai's presence) and Denmark SS (
yet again beating Kido/Hendra) later on. Surely I can foresee
they will still get criticized for many things despite the Swiss SS victory yesterday (eg: waste tax-payers money for QF loss at the previous week's AE)
In my personal opinion, if Malaysian fans are hoping for Koo/Tan to emulate Fu/Cai's and Kido/Hendra's achievements, it's still not too late to wait if they can deliver in their 2nd (2009 in Hyderabad) or even 3rd attempts (I believe in 2011), before making a verdict on Koo/Tan's achievements as
a one-hit-wonder.
As a badminton fan from INA, I find it amusing that they get condemned by some MAS fans'. Coach Sigit Pamungkas will be more than happy to take Koo/Tan in if BAM is to kick Koo/Tan out for
underperforming in the past 2.5 years. Even if the pair ends the career without any more titles, Koo/Tan's achievements is
something that they should never feel ashamed of 
One last bit, there's another undisputed fact that Koo/Tan have the
age advantage, being younger than the current top pairs: Paaske/Rasmussen, Boe/Mogensen, Fu/Cai, and Kido/Hendra
