Is the machine only going to be used for competition hunting ? If so, an X5 is overkill as well as a Vaquero ( in my opinion).
You cannot get a new X5 or X3, but a new Tesoro comes with a life time warranty.
For pure competition hunting, any of the mid range Tesoros would be the best. And they pin point so well, you really don't need push button pin point. I can X a target with my sons Compadre and it's dead on in the middle of the coil. Heck, he is 9 and pin points right on with it.
Now, if you want to use the machine for other applications, then either the Vaquero ( if you want manual GB ) or Cibola would be a great choice.
I had an X5...good detector, made very well and it was an all around great unit. If you can find a used on in good condition for a reasonable price, it may be worth it. Problem is, they were priced so high, that even used ones go for close to $600 with only 1 coil.
You can get a new Tesoro for way less, and get several coils. Even a new Vaquero with the stock and 5.3 inch coil will run you less than $525.