I ran a 450 with 3-5 adapters for 3 years (36,000 miles) and had no issues.
They need to be checked for tightness every month just in case. Modified Smarts in Europe have been running these for about 8 years and I have never personally heard of a set failing. We do have tight regulations on these though, they are made from aircraft grade aluminium and x-rayed after production. I cannot account for the quality of the USA made ones.