Speeds above 4 or 5 degrees per second are possible with the right stepper motors/gear reduction/driving voltages.
Initialization of date/time/location, and align with one or several stars. Align with one-star to quickly get going or more stars to correct for polar axis misalignment, cone error, mount construction errors, etc. for more accurate gotos and tracking (pointing model and refraction compensated tracking is available for equatorial mounts only at this time.)
Meridian flips happen automatically as needed, the software doesn't allow you to pick the meridian side during gotos, but it does provide a command to inform you as to what side of the mount the telescope is on.
The guide commands are for pulse-guiding, centering objects, etc.
There's even rotator and focuser support (for imaging etc; or de-rotator support for Alt/Az mounts.)
Parking functionality includes the ability to set the park position (anywhere you like), park, and to unpark. In addition to placing the telescope in the orientation you designate this saves the alignment model (as long as the mount isn't moved) and PEC index position.
Home commands including the ability to move the telescope to the home position and stop tracking or reset the controller when at the home position for initialization. OnStep even supports home switches on German Equatorial Mounts, so it can automatically orientate the mount at the start of operation.
PEC commands include the ability to record, play-back, read, and write PEC data. PEC is supported only on equatorial mounts, usually with worm/wheel gears. An index sensor is not required but is supported so OnStep can always recover the worm zero index without a need to park.
The Android App allows for initialization, parking, alignment, PEC programming, etc. Along with the Moon and Planets, several catalogs of objects are included for GOTOs: Messier, NGC/IC, Herschel 400, and a named bright star catalog. The Android App can communicate with OnStep across Bluetooth or IP connections.
The iOS App, Gotomote by Satnam Sing allows similar functionality on you iPhone or iPad. The iOS App can communicate with OnStep across IP connections only.
Typical Bluetooth devices include the HC05, HC06, Sparkfun Bluetooth Silver.
IP devices supported are either the ESP8266 for WiFi or the Teensy3.2/W5500 (recommended) for Ethernet. My OnStep "add-on" firmware gets uploaded to one of these and connects to OnStep via. a serial interface. IP devices have both a command channel (for my Android App, Sky Safari, ASCOM, etc.) and a web server.
The Smart Hand Controller (SHC) is a dedicated hand controller for OnStep. It uses a Teensy3.2 or ESP32 microcontroller, OLED display, and button pad to control OnStep. It connects to OnStep by plugging into the ST4 guider interface. Once the SHC is plugged in, the ST4 port is reconfigured for serial communications and passes data to/from OnStep. Like the Android App the SHC allows access to nearly all of OnStep's features. In addition to the usual keys to nudge the telescope N/S/E/W the SHC features convenient "feature keys" at the bottom for adjusting focus, illuminated reticule brightness, guide speed, etc. That's in addition to the numerous features that can be accessed in its menus. The SHC also has a catalog management feature where advanced users can add or remove whole catalogs (or individual objects within) and organize catalogs into menus categorically. The SHC comes with bright star, Messier, Caldwell, Herschel, NGC/IC, variable star, and double star catalogs. Depending on the hardware the SHC has between 5665 (T3.2) and 24606 objects in its database (ESP32, there's still room for plenty more.) ... and you can filter the catalogs by object brightness, constellation, distance, double star separation, and variable star magnitude range.
It is our favorite device when stargazing at the telescope eyepiece where physical buttons that can be worked by feel are preferred over bright touch screens; though a "basic hand controller" (bought or built) can accomplish similar in combination with the Android App.