I'm not sure if folks still peruse this thread but I figure I'll chime in. I've owned the EAR HP4 (headphone amp) for 5-6 years now I guess it is. I've also owned the 834p for nearly the same length of time. Both have worked flawlessly and save for my own curiousness with regards to tube swapping, none of the stock tubes have run out of life. I don't listen all day every day, but I would think it is safe to indicate that I likely listen about 100 hours/month.
The parts list isn't glamorous but then they weren't chosen to be. Tim apparently designs with sound in mind first, then cost considerations but always with reliability trumping both. Ultimately, if something was cost no object and sounded like Sirens chatting in one's ear but only for 10 minutes at a time due to some electronic breakdown, it wouldn't much matter how great the unit can sound.
The only gear I've personally looked at, touched and listened to that surpasses EAR in built quality would be anything by Wyetech Labs.