A good place to start - Senior Developer OpenBet Employee Review

Their technologies are outdated and won't help you find your next job. The direction the company is moving towards looks pretty grim. Loads of buzzwords coming from new senior hires but all I see is loads of old code with not tests, and the first attempt to modernise the company and bring in "products" failed, mostly due to the lack of tests documenting existing functionality. No new customers for a while now as initial costs are too high for most prospective customers.