I worked with Sergey on a couple of projects in IDT corp.
I'd like to notice, that Sergey is competent not only as a Product Manager but in contiguous competences.
He's able to take a look at the product in scale, and it's helpful for the entire team and stakeholders with product strategy vision and solutions.
I actually liked to work with him and highly recommend him like a great colleague and specialist I'd liked to work with again.