I definitely prefer regular suits over any other combination. What I want to say is that if you have to wear businesslike, it is always nicer to wear the same style on both the upper and the lower part of your body. This obviously can best be achieved with a regular suit. It has the same color, the same style, patterns and everything. Some like to include a vest. Anyways, you would have all two or three parts of your suit lined up.
On the other hand you could additionally always wear a combination of two not necessarily matching pieces. Matching in the sense of color and design. The style should match up in any sense. What I mean with that is a combination of any business trousers and some sports jacket or blazer. Most of the combinations I know include a dark blazer and some lighter trousers. For example you would have a dark blue sports jacket and some beige trousers. You could combine all this with some fancy pink shirt for example or a shirt in any other color.
The point is - and that is exactly the reason why I do not like these combinations - that there are too many colors involved. If you wear a business dress, then I always prefer one dominating color that expresses itself through a uniform suit. Anyways, the combination of both is actually something for the older men. Maybe someday it is going to be me also who wears a combination that I would not have liked before.