Here are the key differences between the Xiaomi QiCycle and the Xiaomi Mi Smart folding electric bikes:

## Design and Folding Mechanism
- The Xiaomi QiCycle has a more straightforward but somewhat clunky folding mechanism, requiring several steps to fold the bike, including lifting the seat post and nudging the rear wheel.
- The Xiaomi Mi Smart, while not the most stylish, has a similar folding design but is noted for its bulkiness even when folded, making it less convenient for storage.

## Motor and Power Assist
- The Xiaomi QiCycle is powered by a 250-watt 36-volt high-speed motor with a maximum speed of 20 kph (12.4 mph) when not pedaling. It has three power assist modes: full-powered assist, eco mode, or completely off.
- The Xiaomi Mi Smart also features a motor, but it includes a torque sensor that is supposed to intelligently match power output to pedaling, though it has been noted to have inconsistent power surges.

## Gears and Speed
- The Xiaomi QiCycle comes with a Shimano three-speed internal gear hub and a maximum speed of 28 kph (17.4 mph) on flat ground with pedaling.
- The Xiaomi Mi Smart has three mechanical gears and a top speed of 15.5 mph. The gears are more suited for getting started at lights or easier rides on hills rather than high-speed riding.

## Battery and Range
- The Xiaomi QiCycle has a 5,800 mAh, 36V battery with a range of around 45 km (27 miles) and a charging time of 3 hours.
- The Xiaomi Mi Smart has a battery that provides a maximum range of 25 miles, though specific battery details are not provided in the sources.

## Additional Features
- The Xiaomi QiCycle includes front and rear lights integrated into the main beam and Bluetooth connectivity to track ride statistics on a phone.
- The Xiaomi Mi Smart includes lights and gears, which are notable features compared to some other affordable e-bikes. It also offers various purchase and maintenance options through Halfords, such as interest-free credit and lifetime safety checks.

## Price and Availability
- The Xiaomi QiCycle is generally priced around $450 (approximately €400), though prices can vary depending on the region and availability.
- The Xiaomi Mi Smart is priced at £999 (approximately €1,100), but it is currently available for £999, which is a significant discount from its original price.

These differences highlight that while both bikes offer good value, they cater to different needs and preferences in terms of design, functionality, and features.