If you mean 630 or 252?
It depends on what you want,need in a grinder .
I've owned both in the past ,but got tired of not being able to get it in back yards with the 630.
Now I only have the little 252. It is very slow on big stumps,but in the end ,I have made a lot more money with the portable than I ever did with the tow behind. But we have a lot of nicely manicured lawns here ,and HOs prefer no trucks on their yards.
Some here will say ''the 252 is a toy'' and compaired to the bigger machines they're right.But then again,the 630 is way under powered for a TB, IMO.
Remember this .They all require constant maintenence,and they all break down.
Think about it.
What else do you buy with the intention of running it into the ground?