I personally would not eat a pie that comes off a conveyor oven.
That being said and leaving my personal preference out of it, Business sense these days leans toward the conveyor for many reasons but the main reason being cost effective. Newer conveyor ovens are way more economical than a deck. Heck some ovens go into sleep mode and automatically activate as soon as a order is entered into the POS system. Most older (GAS) ovens are more economical than a deck too.
Another is you don't have to have a $15-$20 hr. Oven person. Keeping employees is sometime a tough chore. Have a shop with a conveyor and the Cashier can sling pies. And IMO the main thing is consistency. Nothing worse than seeing burnt pies in the trash can or backed up during peak hours.. Have a conveyor and their baked right every time and not making anyone wait. Being from up in the North East now In FL I see many New Yorkers switching to conveyor ovens as if your recipe is good you can get a pretty darn close crust with a conveyor if you just gave it some time tweaking the fingers "air flow impingement"
To the original poster my advice would be find a good tech that will work on the side and let him rebuild the necessary parts 1 oven at a time. Replace all bushings and bearings on the chains and motors and keep all fan motors free from dirt / flour buildup and you should be good to go for a lot cheaper than new ovens.
Recommended oven would be a Middleby Marshall or Lincoln only. Parts are plentiful and major repair companies send their techs to the factory for repair training. You also can go for trainings.
There is a reason that the major pizza chain stores use conveyor ovens and the reason is ALL OF ABOVE.