So far my TIU is fine, just a for-what-it's-worth here... I've tried several banana plugs over the years and these are the best I've found EZ-Hook 9202 R/B, nickel plated. They are quite sturdy, don't smash, flatten or loosen up with repeated use like many others do. They also fit very tightly in the jacks and stay that way. I was quite impressed with these compared to all the others I've tried, many of which were more expensive, gold plated, etc. Unfortunately, the price has gone up some, they were only around $4 a pair on my last purchase.
For binding posts (dual jacks), I've been eyeing the Keystone 7109. Looks like a nice one, nickel plated, 10-32 threads, 30 amp rating and appears to be of good quality. Also a bit pricey, but cheaper than their gold plated model 4109. Haven't tried these myself, but might have to order a couple to investigate. The ones I've used lately from ebay are ok, but the threads sometimes seem to strip fairly easily which makes me question the reliability of the connections. I've had a couple just strip out while tightening, for no appearant reason.