in other words you completely missed the point, though i can see why. yes both have their applications, however needle bearings are used in applications where there is little vertical stress in the application, such as roller rocker arms. roller bearings on the other hand as used in applications where there is substantial vertical stress, such as wheel bearings and roller bearing spring perches.
First of all, bearings don't know (or care) about vertical, horizontal, etc....they are designed to take radial or axial loads, period.
A needle bearing IS a type of roller bearing, and because they have a large number of small cylindrical rollers packed together closely, they have a large "bearing surface", which is the total area where the needles make contact with the races. Because stress equals load/area, the large bearing surface in a needle bearing drives contact stresses down. Therefore, needle bearings handle radial loads VERY well, but they don't much much in the way of axial loading.
A ball bearing (which is what is used in roller spring perches) have more space between the ball-to-race contact locations, so the bearing surface tends to be smaller when compared to a needle bearing of equal size.....smaller contact area equals higher stresses. So, ball bearings take radial loads pretty well, but they also have the added benefit of being able to take SOME axial loading.
A bronze bushing creates a very large load bearing area, through more uniform "surface contact", and therefore VERY low stresses. So, for high radial load application, with a small range of motion, where some drag is acceptable, a bushing is pretty much ideal....which is why Ford used a bushing on the early Falcon perches.
So, since a spring perch involves nearly all radial loading on its shafts and bearings, the order of preference would probably be: bronze bushing, needle bearing, roller ball bearing.
Since I'm sure you won't believe me because you're so hung up on "roller" bearings, considers this.....the original Mini Cooper S was basically a purpose built (and very successful) rally car, designed to to take on the harshest roads in the world, and it has its upper control arms mounted on needle bearings. Even though most of these cars have been flogged to within an inch of their life over the last 50 years, I have never heard of a single bearing failure that didn't involve gross neglect. If lubricated periodically, they are absolutely bullet-proof.
By the way, the tapered wheel bearings you mentioned are basically a hybrid needle bearing, but because they have cylindrical rollers (not balls) loaded on a conical surface, they take radial AND axial loads very well. This is why cars switched from true ball-type bearing wheel bearings 50+ years ago.