I just went through this same scenario... so I will give you my story and maybe it will help you decide...
My 65 SF had all kinds of rear end noise at low and high speed. So this winter, it was my intent to pull the rear, clean and inspect and replace anything needed, including the wheel bearings. I found my springs were shot, it had air shocks holding up the *** end...and because of this, was masking that the carrier had dropped to about 15 degrees nose down, putting tremendous stress on the u-joint and drive shaft. Pulled it all apart to inspect everything... once I did, the problems were compiling fast.
I found when I pulled the rear axles out, to check the wheel bearings, the thrust bearing (which is a two piece unit that sits INSIDE the carrier and acts as a pressure surface for the axles to push against in turns) came apart inside the carrier. Each piece fell into its respective side, and the crappy little pin they are held together with broke into pieces inside the Sure-Grip. Well... out came the carrier and I went fishing... I'm telling you this for a reason... hang in there. LOL.
I did a ton of research on the differences between the two bearings... side loads, drive styles... etc. The original tapered bearings vs Green rollers has been the catalyst for the most heated flame-wars on many threads just like this... even the one I initially started as well. It comes down to this... your choice. They BOTH have good and bad aspects. They BOTH do a good job under normal and hard driving and they BOTH have weaknesses.
Tapered are best for side loads, no doubt. But if you are a responsible mechanic, you don't just pull the axles and shove grease in them to pack them... and when you pull them, better look down that tube and make ABSOLUTELY sure the thrust bearing didn't come apart like mine did. If I didn't look down in there.. my rear end would have blown to pieces, or I would have damaged the **** out of the splines when I put the axles back in. To properly pack a tapered bearing, you should remove it, and replace it with a new one... period. An unsealed bearing of any sorts has to be properly cleaned, inspected and repacked properly. Anything less... you're just slapping icing on a cupcake. So... moving on.
Green bearings... easy peasy to install, no maintenance and no adjustments... and NO Thrust bearing. If you switch over to them, you have to pull the carrier and remove the thrust bearing. Some say you don't, but it's sensible to do so. If it fails, that little pin will go who knows where. Side loads are not as strong on the Greens, but unless you're wailing on this thing doing donuts all the time, I doubt you'll ever have issues. What I don't like is that the whole assembly is held in place by a very thick hardened steel snap ring... that's it. Kind like a c-clip on the end, instead of in the carrier. If it does fail... it's REALLY going to fail. But again... highly unlikely unless your really beating the living **** out of your car.
So that's the case... both have to be pressed on, as they are the same installation design. Both will have armies of guys with opposing opinions yay or nay... both do the job very well (Green totally sorted out the issues with the new design).
If this is a car you park a lot, and weekend cruise to shows, then maintenance on the tapered is nil. Once they're properly packed, installed and adjusted... good for life. Greens require NO maintenance for life. They are sealed. Cost is relatively the same, again, Greens cost a little more and a little more work as you should remove that thrust bearing to assure proper fit. Don't have to, but you should.
I hope all this bullshit I just typed helped a little... it comes down to you and what you want...it's your car and you drive it. I went with Greens, and so far, I'm happy, but would have been happy with tapered as well. I put the greens in because my thrust bearing fell apart anyway. I like the design, it was super easy to install, and if I want to pull my carrier at a later date, or even just the axles... no more thrust bearing falling into the carrier.
Oh yeah... and my SF's rear end... well.. she went from a saggy, flat *** hanging low in the breeze... to a tight, firm beach bunny with a tiny pink thong!
