I am tempted to mostly agree with the others. Moving between QMS software is pretty rough, and you're unlikely to have your operations down at the early stage. A number of solutions are pretty immature, and the veneer of quality begins to flake off once you actually put a bit of pressure on the system and check the validation for yourself.
In particular, check validation documentation carefully as a lot of things are simply passed back onto you as a "user responsibility". You will still be required to establish procedures that work with such systems.
For ones I have seen or tried; Greenlight Guru has a very strong marketing prescence - my experience is that it is still inflexible and immature as a solution. Verse Solutions seems a bit more mature and robust (if less pretty), but less amenable to updates and changes. I would be very hesitant about investing in them as a startup.
Keep your requirements to the absolute minimum while you are starting. You need your time and resources to go toward making sure your product is up to snuff, not troubleshooting QMS software. A simple cloud-based system with adequate permissions, and a decent way of recording reviews/approvals and signatures is a good start.
Devil's advocate: technology implemented well will save you a lot of hassle. Your biggest stumbling blocks as a new company are often just keeping track of the enormous backlog of tasks required for medical devices - if you are going to invest in anything, invest in non-QMS systems to ensure communication is effective, automatic, and centralised (e.g. something that reminds people they need to review a document, etc.), and that activities are as visible as possible to everyone at all times. Those tools don't necessarily need to be "official" in a quality systems sense; they're just good business and communication.
Spend some time thinking about how to make it easy for people to be compliant, not just your records.