[Moo] Fx onComplete: set('tween') or chain?

[stratboy]

Hi! If I have to set a simple onComplete event on a tween fx, from a
performance point of view, what's better?

set('tween',{ onComplete...})

or

elem.get('tween').start(..).chain(function(){..})?

For example:

//                      item.set('tween',{
//                              onStart:function(element){
//                                      element.setStyle('display','block');
//                              }.bind(this),
//
//                              //vedi show_next()
//                              onComplete:function(element){
//                                      if(element.getStyle('opacity') == 0){
//                                              
element.setStyle('display','none');
//                                              this.show_next();
//                                      }
//                                      else if(element.getStyle('opacity') == 
1){
//                                              this.show_arrows();
//                                      }
//                              }.bind(this)
//                      });


Could also be (since in fact they are triggered in 2 dinstinct methods
in my class):

item.setStyle('display','block').get('tween').start('opacity':
0).chain(function(){
     element.setStyle('display','none');
     this.show_next();
}.bind(this))

and

item.setStyle('display','block').get('tween').start('opacity':
1).chain(function(){
     this.show_arrows();
}.bind(this))

SO, what's the best practice/approach?

Thank you