The difference between 比～更 and 比～多了 In Mandarin, there seems to be two forms of comparison statements. The first is 比～更, and the second is 比～多了 (or other variants such as 很多 and 得多).
Example:

他打篮球比我更好。
他打篮球比我厉害多了。



坐高铁比坐飞机更方便。
坐高铁比坐飞机方便很多。

I understand that 更 must precede the adjective while 很多 must be put after the adjective. However, except it what kind of differences between these two forms of comparison statement?
By the way, should 了 be put after 更好 and 更方便 as well...?

UPDATE
Let me clarify the point here. My question is about the difference between 比～更 and 比～多了, regarding the degree of the strength. So for example, suppose the following sentence:

他打篮球比我好。
他打篮球比我更好。
他打篮球比我厉害多了。

How should you order them by the degree of the strength? I know the first sentence is the weakest, and just means &quot;better&quot; But the second and third sentences both mean &quot;much better&quot;, and I don't understand which looks stronger regarding the degree, and also I would like to know any differences, if any (e.g. nuances, etc...).
Simply, 


  比～更: even (more)；
  
  比～多了：much (more)；


他打篮球比我更好。： he plays basket ball even better than me. 

他打篮球比我厉害多了。: he plays basket ball much better than me.

坐高铁比坐飞机更方便。: Taking high-speed railway is even more convenient than taking a flight. 

坐高铁比坐飞机方便很多。: Taking high-speed railway is much more convenient than taking a flight. 

Updated according to the updates from OP:

Compared these three sentences: 


  
  他打篮球比我好。
  他打篮球比我更好。 
  他打篮球比我厉害多了。
  


2 and 3 are stronger than 1. 2 and 3 are hard to compare, because they are used for different purposes.