I used the altronics for my first 5 years flying and about 1100 hours. I quickly replaced the earseals and headband with DC products. Did have 1 small glitch with them after about 10 hours - a quality control problem I suspect - which was fixed within 2 days. Still have them as a spare set. Have since had 2 pairs of DC 10-13XLs which are the luxury model but you do pay for the luxury. The second pair was due to me losing the first pair in a burglary in Melbourne in June 2000 (if anyone has them I don't want them back, but wouldn't mind knowing who sold them to you. Unless you stole them in which case just tell me where you live.)
The company I work for now provides DCs so I tend not to use my own headset, but we would replace a gel seal probably once every 2 months - yukky job. Also the noise cancelling appears to work in exceptionally well in every piston aircraft except the Islander. Haven't tried them in the Aerocommander either, though.