If you play on console, there is nothing to decide: the G29 is for PlayStation and the G920 for Xbox, and neither works on the other. The real question is on PC, where both work. There we would pick the G29, because they are the same inside and its rim offers more: RPM lights, + and − buttons and a 24-position dial.

Logitech G29 Driving Force
Who it is for: On PlayStation, and on PC too: the same motor with RPM lights and a dial on the rim.

Logitech G920 Driving Force
Who it is for: On Xbox, where the G29 does not work. On PC, only if you find it clearly cheaper.
| Logitech G29 Driving Force | Logitech G920 Driving Force | |
|---|---|---|
| Motor | Gears | Gears |
| Force (torque) | 2.3 Nm | 2.3 Nm |
| Rotation | 900° | 900° |
| Works on | PlayStation, PC | Xbox, PC |
| Pedals | Three pedals (3) | Three pedals (3) |
| Load cell brake | No | No |
| Rim | Hand-stitched leather | Hand-stitched leather |
| Display and lights | RPM lights | One power and status LED |
| Base weight | 2.25 kg | 2.25 kg |
| Software | Logitech G HUB | Logitech G HUB |
In bold, what differs between the two. Figures from each manufacturer's official sheet; "not published" means the brand does not give it. We do not show prices because they change every week.
Logitech gives both the same figures: dual motors with helical gears, 2.3 Nm, 900 degrees of rotation, three pedals and the same weights. Turning into a corner, the force you get is the same, so if someone says one of them "drives better", they are comparing something else.
Logitech's technical sheets are not the same. The G29 lists RPM and shift lights, + and − buttons, a 24-position dial and Enter. The G920 lists a single power and status LED and none of those controls: D-pad, X, Y, A, B, paddles, two stick buttons plus Xbox, View and Menu. In a single seater, where you change settings mid-straight, that dial is the most useful thing separating them.
The G923 uses the same motor and the same force, and adds TrueForce and a progressive-feel brake. We cover it in the G29 vs G923 head-to-head, which also applies if you play on Xbox: the G923 has a version for that console.