As the main author of the VarDumper component, thank you for this article!
If you really plan to write a “battle of the vardumpers”, let me know 
One main example with all other dumpers is how (hard) references are dumped: with VarDumper, you can inspect/read them. With others, they are at best replaced by a recursion warning.
VarDumper is focused on extracting the highest possible accuracy about any PHP variable. It never fails with highly complex structures nor in any layer of your PHP app (try e.g. dumping in a PHP output buffering handler).
VarDumper is also highly modular so you could build more than one dumper (I would even encourage LadyBug/Kint to build theirs on the state extraction mechanism of VarDumper).
Debugging can’t be done efficiently without robust tools. The xdebug vs dumpers discussion will never end imho because both serve different use cases / group of users (I personally use the two of them).
For Silex integration, you should try https://github.com/jeromemacias/Silex-Debug
And for the ellipsis that show up too fast, I’ve raised the default 250 items limit to 2500, that should help.