As an example, let's take a node with 5 fields and two blocks between those fields. E. g. you want an article do be displayed like this:
Block with related nodes
Block with ads
In D7, such display is quite simple to create with Views - you use contextual filters to output fields and just put two blocks between them.
Another option is to use node.tpl.php and create the same template.
Which of these two (Views with context. filters and tpl.php files) is better performance-wise, especially when it comes to MySql performance?