I have replaced my thumb shifters 2x now on my 2014 Soma San Marco. Each time the right or rear derailleur at about 1500 miles each. I have decided to go to bar ends expecting them to last longer (my '95 Trek 520 & '91 Nishiki Saga have lasted for thousands of miles). This is a 9 speed with a triple front. All I can find are Microshift or Shimano and the Shimano seems to have unfavourable reviews. Question: 2 types of Microshift models seem to be identical but for the price -- a09 and t09. Is there a difference? Is one an old model? Thanks in advance!