We're looking for a Microsoft partner that will help us with our journey into the Cloud, providing consulting, cloud architecture and documentation services.  Does anyone have experience working with a company called Tek Systems?  If not, do you suggest any other companies for a multi-national organization?

We have used Ricoh and Kainos, both we would recommend 

I have used a company called BlakYaks based in London. Very high quality engineering & automation. 

I've used them for staff-aug contractors, and have never felt that they weren't open to feedback or willing to accommodate requests.   

While I haven't worked directly with their managed service offerings, I've had a fantastic time collaborating with them on three different occasions, providing consulting services. I've also engaged other contractors through TekSystems, and they've consistently impressed me with their ability to find the right talent. Given their strong track record in placing individual resources,  their managed services should reflect a similar level of quality.