Comparing apples to oranges... I had a case crack on my Lycoming IO-360, not that unusual, what with 200 horses stuffed in one stable. I looked into having the cracked welded by Divco. Based upon the photos I sent they said it likely could be welded.
However, perusing old emails on the Cardinal website showed that several people had their welded cases crack again within a few hundred hours. Now, I don't know if it was due to poor repairs, or this engine was prome to cracking and not a good candidate, or what. But it certainly gave me pause. In the end I lucked into a first-run overhaul engine.
Good thing, too. It turned out my cracked case had been overhauled several times already, and the deck height was too low to machine again. This probably explains why it cracked, too - too many fatigue cycles.
So, in my opinion, I would opt for the case from your mechanic as opposed to welding yours, especially if it has lower time.
Which brings up another point - it can be very difficult to determine how much time is on a case (or any other engine component). The only thing the engine logbook really tracks is the data-plate. Everything else can be swapped with no continuing record of time.
