That is really a matter of personal taste. Meng is a high quality manufacturer but that has little to do with it. Tamiya is know as one of the HIGHEST quality manufacturers yet their armor kits are some of the most simplified and often require the most work to bring them up to the detail level of say a Dragon or Bronco kit.
Rarely does a model NEED a upgrade set. Now as modelers we choose to add them, myself included. On the other hand... A well built and painted box stock kit can contest well against a lesser built kit stacked with AM parts. Also, a few small scratch built items can go a very long way and are generally cheap and fun to do.
Thats my 2 cents on the issue. Hope it helps in your decision.
-Kenneth