Rear Bearings Installed...Question of Quality

[WYOSVX]

I bought NTN rear bearings for my SVX, the passenger side rear was pretty loud.

I cleaned them and re-packed with lithium-based, high temp bearing grease.

Stupid thing: While blowing out one set, I got the race (cage) spinning pretty fast, making a cool whirring sound for about a second, then it exploded. Lucky I didn't lose an eye. My bad. Expensive fun. Ordered a replacement.

Ran out of time, want to drive my car, so took it to my mechanic. I've found him to be highly qualified, over the years; at least for our small town.

He had their assistant do the job. He broke a set during install, something about over-torqueing, wheel not turning, backed off the torque- too late. They had the printout I gave them to tell them about the SVX bearing oddities and I made a point of telling them before without being the know-it-all shade-tree mechanic. Judging by the greasy smudges, they read it. Again, they're good mechanics. I probably would have screwed it up, too, then had to wait till I had more time to fix my screw-up again. They paid for the bearings.

I think AP Warehouse is okay with replacing a broken set, as it was installed by a qualified shop.

Here's the question:

NTN bearings have plastic holders (cage) for the bearings. My mechanic said that, at least with GM, they went with those over metal to make them quiet but they haven't found them to last as long as metal. He likes metal.

I talked to AP Warehouse, they weren't sure which might be metal, but, at least, Timken were plastic. That leaves Beck-Arnley and NSK, that I know of.

Any opinions? Metal vs. plastic?
Any personal experience?