Rich, I have that exact unit except for the white paint i got green.
Here are my experiences with it.
I bought mine direct from store and brought it home and assembled it.
At the time they had claimed it had a magnetic starter switch which i knew was not correct but even on inquiring in the store and having them check they said yup it did. So when i got it home and checked i ended up having them ship me a mag starter for free and fitted it myself.
So be aware there is no mag start switch on it, and i think that for a 3 hp 4 knife dangerous machine like that it should have. There is no problem fitting one many locations to do that.
Then the next thing that was and still is an issue to me is the fence. It has me thinking of Carols words of when everything is adjustable its usually a marketing thing and adds to issues in use.
So this particular design fence is pivoted off allen screws that are pointed and rest in corresponding cavities on the casting behind the fence. We are not talking here about well seated bearing surfaces. Just a drilled hole which ends up getting powder coating in it and the cap screw pointed to rest in it.
I had so much play and was afraid if i tightened these screws too much it would snap the casting off. There is a kind of H in the casting that provides for the swivel/tilt of the head for doing chamfered jointing. The pivot points (there are four of them) are on the 4 points of the H.
Grizzly was helpful and sent me additional allen screws and their answer was to tighten them up. But you can see the conflict i had and at the time being across the border and Grizzly at the time not publicly shipping to Canada as they do now, i did not know what would happen if they snapped. So i set it best i could and lived with the issue.
The result is the fence moves out of 90* relatively easily so i just check it frequently. Its really my only beef with this unit.
Note i am not a pro or even a retired hobbiest so my jointer does not get the use others may put one through.
It was not until a week or so ago that i first sharpened my blades and reset them and checked the beds properly.
I did discover my outfeed table had a dip but i could not find a spec anywhere so decided to not worry about it since my warranty is well past.
So i would ascertain upfront what flatness spec the machines Grizzly sells are meant to achieve for any new machine i buy next time.
I have also had the start capacitor pop on me but thats a normal serviceable item and i am still not convinced i did not cause that myself running the machine off a generator.
Were i to buy again, I would look to buy the G0490, with the parallelogram beds a magnetic start and if i recall correctly a different fence. It is in my mind a clone of the successful delta DJ20 unit at a more reasonable price.
One nice thing i discovered about the 656 is the head. It has four cutters and height adjustment allen screws that make setting knife height easy. Not spring loaded type rather fixed screw height.
Of course were i to buy again i would go straight to the shelix head type carbide inserts cutter head and not think in terms of later retrofitting. There is no doubt in my mind this is a feature that will payback very quickly especially for a person that does the amount of work you do.
Consider how long you will own the jointer and in that time how much time (in your case is money since you do pro work) you will save when for some reason or another a nick has occurred and with a simple allen key and rotation of the single cutter you can remove the nick and keep on jointing.
Never mind the benefit for a person like yourself when it comes to ornery woods and getting a decent surface quickly.
Rich i have insert a image from Grizzlys site that shows the fence setup you can see the locking nut heads on the H sections of the casting supporting the fence i was referring to. A careful look and you see how much meat there is in the casting that has to resist the force exerted by the adjusting screws. I am not saying they will break off, I just never wanted to find out. May do so now that Grizzly actively ships to Canada.
Best of luck with your choice. Its once again one of these things where we have to decide on where we settle on price. Note in your case you should be able to depreciate it for tax purposes. In fact you should check with your accountant because in many cases in the US small business situation a value like this can be written off against income in total in the same year.
Other than my meager gripes its been a good machine and done the job. Note though, i emphasize i am not by any means a frequent user.