Both of those brands are good quality belts.
Coincidentally, I have just opened one of my Volvo boxes to look for a relay and here's what I saw.
See pictures attached...
All of these belts were manufactured by Continental (Contitech):
a timing belt for the old version d24t, an injection pump belt, an alternator belt and a power steering/accessory belt.
In fact, now that I am looking at the date stamps, I would like to ask the pro dieselers this: are these still good? Do these expire (even if kept in good cond?)?
According to the labels on the original boxes, these belts were manufactured in 2015 Sept and 2016 Jan, which was a long time ago... but I had them stored in dry storage, they were not bent or twisted or loaded upon, no light/sunlight, no extreme temperatures, no UV exposure, etc, "not even air" as they were stored in a lockable gun case. I know they don't belong there except maybe the timing belt... that can be a dangerous
weapon against the interference engine.
I was supposed to use these belts up several years ago for one of my spare engines but I haven`t finished those.
The belts still look perfectly new but I will dispose (or keep) them according to the replies I receive here. ACTUALLY IT ONLY MATTERS FOR THE TIMING BELT, the other belts are much easier to replace and there's no damage when/if those fail.
If the part numbers are not visible, I can modify my post later to include them. JPliddy, is your car a later year, euro model d24t-TIC with the hydraulic tappets? Your car *might* need a different belt from what I posted.