Compared to the original one? No... of course not. You get what you pay for.
Original grip for D700 is made of magnesium alloy. 3rd party one is made of plastic.
Original grip is weather sealed. 3rd party one is not.
And there are cases of where the phottix grips (and other 3rd party brand) suddenly stopped working after a firmware update.
There are 3rd party grips that break after a while.
Then again, there are many people who use the 3rd party grips who did not run into any problems.
So it is your call actually. The MDB-10 is selling quite cheap used in BnS recently. If you cannot afford a new one and really need one, you can buy in BnS.
He decided to smash the Phottix grip as a protest... BECAUSE his Phottix grip stopped working after a few months, after he upgraded his firmware on the D700.
And in case you don't know, the original grip will not smash as easily, it is all metal, magnesium alloy, just like your camera. Phottix is all plastic, you can buy similar 3rd party grips in China for around $70. And one particular brand at that price (called Meike) actually performs better than the Phottix one.