NT520 Pro is also a good option... here's the Gemini Pro summary of the differences:

While the software functions for a given car are the same, the NT520 Pro introduced several quality-of-life and compatibility improvements over the older 510 hardware:

Upgraded Hardware: The NT520 Pro features improved internal processing hardware designed to make boot times and scanning slightly more efficient compared to the early NT510 platform.

Easier Updates: With the original NT510, updates usually required physically removing the MicroSD card from the device and plugging it into a PC card reader. The NT520 Pro allows you to update the machine directly through a standard packed USB cable connection to your computer.

Expanded Vehicle Brand Support: The NT520 Pro expanded the registry of downloadable software modules, adding deeper coverage for brands like Mercedes-Benz, Lancia, and PSA (Peugeot/Citroën) that the original NT510 struggled to support or didn't offer.

Legacy Mercedes Support: The NT520 Pro configuration opened up compatibility with a proprietary 38-pin analog adapter configuration to read older chassis (like the W210 Mercedes), which the standard NT510 hardware pinout couldn't talk to properly.