Pros
Some of the top hedge funds and trading firms have hired early-career professionals with a few years of experience from Numerix. In my team, from 2021-2023, two quants went to Susquehanna and one went to WorldQuant. Another went on to do Part III Maths at Cambridge. I think in particular the fixed income experience is valued by macro hedge funds, exposure to all the factors driving fixed income (interest rate/inflation/credit risk etc). The broad experience you get across products sets you up well for this. Many people have also stayed a long time at the company and in my opinion this is a testament to the company culture. During my time there my managers and HR were extremely supportive and I found most people to be amiable. For quants, once you get up-to-speed with company software there's opportunities to get experience leading quant modelling projects from an early stage which is also very valuable. This can involve meeting the client virtually, understanding what they need and then deciding how best to design a model to meet their requirements, before implementing it using company software.
Cons
Overall only minor from my time there. I heard rumours of the starting of a machine learning lab at Numerix but this didn't seem to be marketed very much across the firm.