I wouldn't expect you'll have a significant difference in reliability either way. TRW is a huge company worldwide- they are a big name in OEM suspension parts. I would *hope* they know what they're doing....
You're going to notice an improvment right away with the new parts no matter the brand. I would agree that generally, the Volvo brand is superior and the no-name brand inferior. If it's european made, it's almost certainly just fine. China, Taiwan, Korea = crap.
The reason there aren't boots for sale is because that's not what fails. If the joint is old enough that the boot split, it's time to replace it. Not like old cars where you would grease the joint, they're "permanently" greased. So just replace them, you'd be doing all the labor to get at it anyway. That's where the money is, in labor. IF you're replacing them yourself, you will be saving the majority of the price of the job.
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Rob Bareiss, New London CT ::: 86 244DL, 87 244DL, 88 744GLE: 625K total