I've had two sets of Spidertrax spacers. 1.25" ones on my Tacoma and 1.5" ones on my Cruiser. Spidertrax seems to have some proven reliability with very few failures (none that I'm aware of) when they are set up correctly. Make sure they are torqued correctly and use red Loctite. Check the torque periodically and you shouldn't have problems. I have tens of thousands of miles between the two sets I've had and so far so good.
I got the same spacers on my 80, but im noticing some slight vibrations around 40mph and 70mph. Any suggestions?