His action first. Here is a frank and reasonably fair assessment of the great Murali's action from that other great Warnie:
"Murali's action has been passed by scientific tests, I always thought it was probably legitimate," Warne said.I loved those last words from Shane Warne. I find it quite possibly the main reason for various umpires outside Sri Lanka crying foul on his action repeatedly even though his bent elbow looked all right to me (and Warnie) by remaining bent till the end of delivery. These umpires, catastrophising on the impact that his action could possibly have on young minds, probably desired to stop Murali more as a precaution than to punish his actual bowling action.
"But because of the way he bowled, I was worried that young spinners would try to copy his action and end up bowling illegally."
Now to his achievements and the other 'calls' on his reputation. This cricinfo feature, apltly titled "An Unparalleled Match Winner", dwells on various notable career stats of Murali. It reminds our forgetful minds of the magnitude of achievement he is leaving behind, besides the small matter of returning a ratio of almost six wickets per Test.
For starters the man has taken 560 Test wickets since 2000.
We often hear a lot of comparison with that other spinning great Warnie of the 700 plus club. At times partisan cricket followers suggest that Murali's stats are inflated ONLY due to Bangladesh and Zimbabwe tours. S Rajesh does a favour to Murali's argument by presenting a stat for "Best bowlers between 2000 and 2008, excluding Tests v Zim and B'desh (Qual: 150 wkts)".
Under that particular stat Murali still comes out tops over Warnie in the averages, while Warnie returns a better strike rate. Considering quality of Murali's bowling support compared to Warnie's, a better strike rate for Warnie is expected as he found more favourable situations to take wickets and was seldom used as a stock weapon. Murali's better average is still a credit to Murali.
[Note: Bagging more wickets per match is an advantage Murali derived from having lesser bowling partners, and tha is why we are not discussing that. I believe Warnie too would have bagged close to six wickets per match had he bowled for a lesser bowling side than Australia - but perhaps his average and strike rate would both have been worse]
PS: This link has another post on Murali's retirement.
Update 1: If you are a Murali fan you may like to go through Rob Steen's excellent piece on the 'Ultimate MVP'