Based on a few articles about elliptical trainers the magnetic resistance is the highest quality for a couple reasons:
- Lower maintenance as there are few to no moving parts
- Provides a quieter machine with less annoyances
- Quicker to change resistances
- Provides more precise control on resistance
- Anyone who has used an elliptical at a modern gym has used magnetic resistance.
Of course, all that comes at a cost: specifically manufacturing costs. I've used a couple belt resistance machines that were not elliptical (primarily stationary bikes), and the difference in the consistency of the resistance is noticeable. The big question is whether the difference is so big that it justifies the price tag. Here are some differences between a commercial facility and your home:
- A commercial facility has to keep equipment in good shape for hundreds of users every day
- A commercial facility has to minimize bad press due to faulty or just crappy equipment so it can keep attracting new members.
- A home has only a handful of people to satisfy--and in many cases only one that will use the equipment regularly.
- Your personal standards may not be so high as to require the very best.
The bottom line is for a home budget you have to get the most bang for your buck. I don't have any information on how often machines of a certain type break down, or typical repair costs.
As to your friend's assertion that the magnetic resistance is better for your joints, I don't think that really applies for elliptical trainers. If your foot were coming off the machine and landing back down on it, there might be something to that claim.
As to general guidelines for purchasing home gym equipment:
- Start with your budget first. You can sink a lot of money into a home gym, depending on what you want to buy.
- Find 2-3 options that seem to be the best within your budget.
- Find a store that sells those items and give them a test drive.
The more moving parts, and the fancier the equipment is (ellipticals certainly qualify), the more a test drive makes sense. In contrast, if you are looking at a barbell and weights, those things are very uncomplicated in comparison and probably won't need a test drive.