A magnetic pick-up helps you retrieve that screw you dropped into the computer. At AU$8.95, you only have to save six minutes to cover the cost of the tool. Each dropped screw is one minute if you can turn the computer upside down to shake out the screw and ten to twenty minutes if you have to remove panels and internal hardware.
There are cheaper tools on the market but they have cheap magnets. All the magnets will pick up a screw. The stronger rare earth magnets are small so they slip into tight spaces and they pick up items that are many times heavier. The strong magnets pick up those metal bracket strips that slip off down under the motherboard and between the RAM DIMM cards. For a couple of dollars difference, the superior magnets are a far better investment.
There is not much else to choose. A long telescope could be useful in a very large computer or when you drop something down behind a cupboard. An illuminated tip could be useful in dark spots but the few illuminated tipped magnetic pick-ups I have tried are too thick to fit in the tight spaces where you need to retrieve screws.
You can also use the magnetic pickup to pick up bolts and washers dropped by your girlfriend/boyfriend/partner/wife/son/daughter when she/he is servicing her/his SSC Ultimate Aero/Peel Trident/Dodge Ram 3500.
A magnetised screwdriver will pick up most lost screws from a small to medium desktop computer and most are not long enough to pick up dropped screws from larger computers or servers. If you work on anything larger than small desktop computers then you need a magnetic pick-up.