Forrester's best days are behind them. Their product innovation is non-existent and while much of their research is valuable, their products are not relevant in today's market. Company decisions are driven by anecdotes rather than data. Which is ironic because they write plenty of research on data analytics. This is partly due to the fact that their data architecture and analytical capabilities are lagging behind more successful companies. They don't do any A/B or hypothesis testing and most decisions are made on the gut feel of the highest paid person in the room.
If you're looking for a job with plenty of work/life balance, Forrester could be a great fit. If you're looking to work with aggressive people who will work extremely hard and push you to become better at what you do, you might want to look elsewhere. There are way too many middle/upper management employees in this company who provide little value. At Forrester the person who has been around the longest will get the promotion regardless of merit. The person who has been keeping their chair warm the longest, usually wins here. As a result they have high turnover and are way too top heavy with too few "worker bees."
Lastly, they lost a star in my book because their HR department (which they call employee experience) has made such a strong push over the past year to encourage employees to leave (favorable) glassdoor reviews. I've even heard of them scheduling meetings on employee's calendars for the sole purpose of having the employee leave a review while HR is in the room. I think this defeats the purpose of an unbiased resource like glassdoor, where employees should be able to choose if they want to leave a review or not. I get that you want to have a good GD rating, but instead of focusing so many HR resources on GD reviews, focus it on improving the company. This doesn't mean more happy hours this means listen to employee feedback, listen to customer feedback, listen to your own research and you will achieve a better glassdoor rating organically.