EBS master program ia generally speaking a good progeamme. Despite some difficulties in the undergraduate program, EBS managed to maintain a good reputation for the master programme. see also the FT ranking. I advise to look also into the details of this ranking, as the financial times provides details for the distinctive ranking criteria.
For job prospective after graduation other aspects are also crucial. Most prominently the internships you did. In Germany, quite often an internship will lead you to a full-time position at the company (perhaps not in the way that you directly sign the contract after your internship but the internship gives you an huge advantage).
For finding a job and an internship in Germany it is most adviseable to know the GErman language. As you post in an English-speaking forum I assume that German is not your native language. So be sure that you know sufficiently German (assuming you are searching for positions in Germany). Not at the end of your studies, but at the time you apply for positions (this might be rather early!)
Regarding Marketing: My perception is that there are relatively many students doing Marketing concentrations because they consider it as easy (personally I do not think that it is easy). Therefor there are in tendency relatively more applications for Marketing than for other functions. However, if you know also "hard-stuff" Marketing (e.g. market research methods, statistics, analytics), this can give you the edge.
Another point is that as Marketer you should have an understanding for the people you market to. As a foreigner to market to German audiences mighte be difficult, while you can provide an advantage for the company to access foreign countries (esp. German startups search for internationals for international roll-out).
You stated that you are a mechanical engineer. Be aware that typically business MSc programmes in German are designed as consecutive programmes ontop of a business-related bachelor programme. While I know that EBS is less stringent in this matter, in the beginning you might need to catch up with others who know already business fundamentals.
I could imagine that in combination of Mechanical engineering undergraduate and marketing-focused business master, there are good job opportunities in the B2B / Sales area of manufacturing companies (e.g. Maschinenbau). This is also not the typical FMCG area many marketing people head to.
Whether the monetary investment is justified is not an easy question. It is most certainly a good programme. Nevertheless there might be better programmes and/or less expensive programmes for you.
I hope this helps you. In case I expressed myself not clearly, please come back to me.