The battery issues with the Macbooks have already been resolved. The issues were when the Macbooks had the Core Duo but switched over to Core 2Duo last year.
One may hear issues about Macbooks but be sure to pay attention to which part. If it is hard-drive failure, its the manufacturer's fault (Toshiba, etc), not Apple. If it is RAM, its the manufacturer's fault (Hynix, etc), not Apple.
Many have had mixed feelings about Dell. Some excellent, others poor. Those who switched over to Macs actually had Dell notebooks which had caused many problems.
Of the two Macbooks I've owned, no issues at all. I've owned Toshiba, Gateway and Sony and the Macs have been the most reliable.