I am wondering whether there are tendency for someone to build a startup using the technology their former employer use. So do you use the technology your former employer use or some other technology that you think more hip than what your former employer use? What are your reason to use one and not the other?
If some employee is working for given employer, he is an expert in a given technology that the employer use. So, it is expected that he will use his knowledge in the startup latter.
Another question is the usage of proprietary technology and non-competitive clauses that are part of the work contract.
When selecting the technology to use, in any new project, not just a new startup company - what should be most important, in my view, is what technology the team members are most skilled in.
It doesn't have to be the latest, most hip, greatest technology. You want to be productive, and what makes you productive is using a technology you are experienced with.
Having said that, it's very likely that when starting a company you'll be using the technology your previous employer used. Not because that's what they used but because you worked there and used that technology and probably that's what you're most experienced with.
Both approaches can be fine. If you have a good reason to switch technology, starting over is a great opportunity, but it's an additional risk. If you think you can attain your goals with the technology you already know, it's one less risk and you'll be ready to go faster.
Of course, you should consider other aspects of that decision. Here are just a few: