I worked at Link Consulting full-time for over 5 years.
Pros
The colleagues are mostly nice, some people are hard to work with but it is not the norm. The salary was good when I first started but then it took a very long time to get a noticeable raise in salary. You will only get good raises if you have a counter-offer from another place and they really need to keep you in the company. The working hours are mostly flexible, depending obviously on each project (some have daily scrum meetings early in the morning). There are some exciting projects, depending on the technologies you are interested in.
Cons
There is a lack of people for certain technological stacks, which leads to some people getting overworked/overburdenned with many projects. Career advancement is very difficult and is not clear enough. Even if you have great performance reviews you will mostly stay in the same position for a long time. I don't believe the company (the higher management at least) values their biggest asset, the people that are skilled and make most projects work.