There is no such thing as the perfect breed - just the perfect breed or breed combination for your specific situation. The key is in very clearly defining what your goals and expectations are for your cattle. And if you change your goals, you should always re-evaluate your breeds to make sure that it is still right for your new situation (such as switching from selling into the conventional auction system to beginning a grass-finishing program). Some things to ask yourself before making your breed choice are:
What kind of climate and environment do you want to raise your cattle in?
How hot is it, how cold does it get, are your cattle going to be on wet boggy soils or gravelly soils or climbing rocky mountains?
What kind of parasites are in your area?
If you are grass-finishing, at what age and weight are you looking to finish your cattle?
Every breed has different historic conditions that they come from which will give them advantages or disadvantages in different situations. For example, if you expect to grass finish calves before their second winter, then you need a smaller framed breed that finishes at a lighter weight, like an Angus that finishes as young as 16 months and 1050 lbs, and not a larger-framed breed that needs several more months' time and several hundred pounds more weight to reach its ideal target slaughter weight.
Tropical breeds are generally more parasite resistant than British or Continental breeds, but they also finish MUCH heavier, so if a farmer lives in a seasonal northerly climate, they should only consider them if they are prepared to overwinter them an extra year. Pasture is cheap, stored feed (hay, silage, etc) is expensive. In hot climates, tropical breeds will continue to thrive in the heat while British and Continental breeds will begin to suffer (and weight gains will drop off) because they are not built to dispel excess heat as efficiently as tropical breeds - they essentially spend all day with the equivalent of a fever. On the other hand, many of these British and Continental breeds are built to conserve heat in cold climates, which makes them more suited for winter grazing programs in northern climates.
If you are raising cattle that will ultimately end up being sold back into the conventional auction system and wind up being finished in a feedlot, then mixed breeds (breed combinations) are a way of combining desirable characteristics from multiple breeds. But, that also means that there will be a huge variation of bone sizes and target finishing weights in your herd, so that not all animals will finish at the same age and weight. If grass-finishing your own animals is a goal, then using a single breed is something to consider as there will be more consistency in the size, weight, and thus more predictability to the length of time it takes to finish your cattle for slaughter, which allows you to design a more predictable beef production and marketing program.
Having said all that about breeds, always remember that there is as much or more variation within a breed as there is between breeds. Evaluating the culling practices of the individual farmers and breed stock sellers is just as important as your breed choice.
I recommend you read my article on choosing your beef cattle breed as well as the Genetics and Breeding: Selecting the Right Animals for your Herd chapter of my book to learn more about how to put together the ideal breed choice for your situation. And talk to some of the commercial cattle producers in your area and find out what they are using and get some of their recommendations for what you want to do with your cattle - commercial producers are not going to be loyal to any breed - they will objectively pick the breed or breed combination that works for their situation and ruthlessly switch if something isn't working.
I also noticed from the tag under your name that you are in Anjou, France, so depending on what your goals are for your cattle business, you may want to include Maine Anjou cattle in the list of breeds you consider since this dual-purpose breed actually originated in your area and will be adapted well to your climate.