Though both NighSky and StarLab have similar feature sets, the two devices are still very different from each other.
The form factor is completely different between the two devices where NightSky is a three footswitch guitar pedal that comes with its own power supply, and StarLab is a 3U, 28hp Eurorack module that requires power from a Eurorack compatible power supply.
As a guitar pedal, NightSky is designed to receive both instrument and line level signals up to +8dBu or about 5.5Vpp (volts peak-to-peak). StarLab is designed to work with hotter signal levels from a modular synth with a max input level of 20Vpp or about +19dBu.
NightSky has a DRIVE parameter with adjustable gain as a secondary function that can be placed in one of two locations in the signal chain. On StarLab, there is an adjustable INPUT GAIN parameter which can provide soft clipping drive as it is turned up on the face of the module which is placed just after the inputs and before the reverb and delay processing.
StarLab features control voltage inputs for external control of 18 different parameters on the module and for recalling the selected Favorite preset. These inputs can also be used to trigger the Karplus-Strong string synthesizer. On NightSky, you can use external control such as an expression pedal for realtime control over any of the knob on the face of the pedal, a MultiSwitch Plus for preset control or to enable/disable different sections of the pedal, or via MIDI to recall presets and control any of the available parameters.
The reverbs on StarLab are based on the same concepts as those that were designed for NightSky, however, they are not the same algorithms.
On NightSky, pre-delay time is available as secondary function without any additional control of the pre-delay feedback. On StarLab, pre-delay is available as a top-level control with the DELAY/TUNE knob when ECHO ON is bypassed. When ECHO ON is engaged, it becomes a dedicated delay effect by bussing the delay output to the WET output mix. There is also a FEEDBACK control to set the amount of pre-delay or delay repeats.
On StarLab, the DELAY/KARPLUS section can be set to operate in Karplus-Strong mode which provides a delay-based, monophonic string synthesizer which can be triggered and pitched via the on-board controls or with external control voltage. This feature is unique to StarLab and is not available on NightSky.
NightSky has a built-in eight step sequencer where each step can have an independent SIZE/PITCH parameter setting for creating rhythmical pitch patterns with the currently loaded reverb settings. This feature is unique to NightSky and is not available on StarLab. Instead of a built-in sequencer, StarLab allows for external sequencing through the SIZE/PITCH CV.
The LFO section on StarLab is very similar to the MOD section on NightSky providing DEPTH, SHAPE, and SPEED controls to modulate 3 different targets. The difference here is that while you can modulate the delay lines within the reverb structure on NightSky, StarLab allows you to modulate the DELAY/TUNE control affecting the delay time or the pitch of the string in Karplus-Strong mode. Modulating the delay on StarLab also allows for classic modulation effects like chorus and flanger. In addition, StarLab has CV inputs for EXT LFO IN for using an external LFO to modulate with, and LFO CLK IN for quantizing the speed of the LFO to an external clock.