I bought a used Blazn Grand Slam about 15 months ago that was in OK shape and was a great price, but had no ignitor rod installed (2 new ones came with it) and the LED on the controller is not readable.  The wheels had tubes in them and were not in greatest of shape.  I replaced them already as it was not very expensive to do.  I have been manually starting the grill with wood in the fire pot.  Once it gets to a good flame, I turn on the controller to start the fan and the auger.  Everything works fine then.  The controller itself works, but you can't read the numbers on it.  I believe this grill is about 5+ years old.  I am debating on whether to keep it or not.

If I were to replace the controller, what would you recommend and why?

I am evaluating whether I want to sink some money into this or not.  I fixed the wheels.  I bought a new chimney stack with stainless top that I will replace the old one that is filled with creosote and leaks at the top and on the body of the grill where it connects.  Installing the ignitor rod may be in the plans since two new ones came with the grill.  I like the rack system that Blazn has to offer as an accessory.  If figure that if I upgrade all of this other stuff and keep it, I may as well replace the controller too.

I have a MAK 2, a Memphis Elite, and a Traeger XL so I don't have to keep this as it is not my only smoker.  I like cooking chicken wings on this Blazn though, and I think the low heat on smoke mode will make some good jerky during decent weather.  I am considering keep it for those two types of cooks and maybe for small cooks too.

I would call Blaz'n and get one of their newer controllers.

With the equipment you have, why not just get a Ortech and keep cooking. Lowest cost solution, no loss of smoke at lower temps that some users report with PID based controllers.

Tim can clean the control readout (pellet dust is the culprit) so you can see it nicely.  Also it is easy to replace the hot rod (if it is the right one).  Under the belly of the beast is a trap door held on by six? screws.  You remove and can get to the hot rod for removal.  Tim can send you the directions also.  Then you are back in business like new.  My GS hotrod just went out after 2.5 years.  I don't think that the new ceramic starter can be retrofitted on the old pot but have asked Tim about it today.  Will report when I hear from him. Best to you and let us know how it turns out.
 

There is a guy on the blazn owners facebook page that is running a Savannah Stoker V4.5's Smoke as his controller. Maybe a consideration.