Should I buy a corded or cordless Dremel rotary tool?

It depends on the work. Verified-purchase volume is heaviest on the corded 4300 platform, which buyers favor for sustained, higher-torque jobs like grinding, cutting and wood carving where you don't want to manage a battery. Cordless models like the 8240 and 8150 trade some sustained power for portability and convenience. If you do long benchtop sessions, corded is the safer pick; if you work in tight or off-grid spots, go cordless.