Macs are pretty reliable, but mechanically, they are NOT any more reliable than other top tier names like a good dell studio and XPS series, falcoln northwest, alienware or hp. However compared to off-branded PC's like acer, gateway or other no name brands, yes they are more reliable.
A REAL claim to greater reliability may only be made if you consider how many third party software aps and hardware drivers there are. MAC is a monopoly. You can only write a mac ap or make mac accessories if you PAY A LICENSING FEE, which most "off brands" aren't going to do. Subsequently, third party mac accessories DO tend to be a little better.
Part of what you're paying for is moving to the top shelf with the rest of the "good" brand names. Apple IS a top tier name. Apple tech support is a LITTLE better than MOST PC tech support, but it is still really bad.
The reason why macs are expensive is because youre paying for :
1. the name
2. the pretty logo
3. some of the best ergonomics and industrial design in the business
4. apple is a monopoly so there is NO competitive discounting.
You will also pay more to upgrade
pay more to repair
pay more for accessories
pay more for software although you can run just about anything with bootcamp.
"CC of oz" is completely wrong. macs can and do get viruses. It's just that fewer people write viruses for macs because the "target" is a smaller audience. Microsoft spends much more time and money being proactive and hiring "white hats". There are several mac exploits that have been known about for months now that have not been patched or updated. As of this writing, there is currently one HUGE hole that has been known for months, but little time and money is being spent to fix it
Macs did tend to be a little faster in the old days because they were using reduced instruction set (RISC motorola) hardware. Now days they are use intel chips and are about the same as PC. In the old days animation used to be rendered on macs, now animation and movies are now made on HP's and Dells. Most scientific work is done on mainframes, but there are alot of very powerful XPS, poweredge and precision workstations at our "national labs" and military bases because mainframe time scheduling is very premium.