Pros:
- don't have to middle click to close tab, which is useful when not using a mouse.
Cons:
- all tabs get significantly wider to accommodate the close button.
- may accidentally close the tab while trying to select it by clicking.
Neutral:
- having close button is more consistent with Web browsers, however there are way too many differences in how IDE and Web browsers are used. The main difference is that switching between the tabs happens way more often when programming in IDE than when browsing.
Please vote and state additional concerns for or against below.