I had a pair of ER6i's that I loved, but they finally went bad. I bought a new pair of MC5's to replace them about 3 months ago. Of course, a week before the region 6 Country Roads meet the MC5's started to act up. I called customer support and told them of my situation and how much I would love to have my earbuds for the upcoming trip. I learned two things: 1) Renee' at Etymotic rocks. She went above and beyond to help me with the very limited time I had before my trip. 2) Etymotic has a special purchase program for their products that are out of warranty. If you have a set of Etymotic earbuds go bad out of warranty, you can send them to Etymotic and get a greatly reduced price on a set to replace them - who knew? So my MC5's were replaced under warranty, no charge. I sent my ER6i's to trade in on a pair of HF5's for $89. The HF5's fit as nicely as the ER6i's did and sound awesome.
Just wanted to comment on the good customer service and let people know they have a special purchase program for out of warranty items that is worth looking into.
My ER6is just died; one driver is apparently out (and I've replaced the filter).
How well do the HF5s fit under a helmet? They look HUGE