You've never said the nature of your problems, Garrett would likely repair them for free unless it was a matter of clear abuse.
If you are rough on your equipment then you can expect failures no matter who makes them.
I fancy myself as fairly rough on mine as well, I dig and probe with it all the time. I did take the precaution of putting a rubber cap on the nose for protection, maybe that helped.
Just by looks, the minelab doesn't strike me as an instrument that would stand up to rough use. The garrett is snout shaped, with no discernible body/neck, it is all a single blended shape which is a + for structural rigidity.
The minelab has a body and a neck, and I'd predict that where the body and neck meet is precisely where it would snap in the hands of someone like you or me.