When I saw your question, it reminds me of my old academic advisor who used to ask me the same question: "Do you want 2 'pennies' or do you want 1 'dollar'"?. He wanted me to publish on high-impact scholar Journals. In the viewpoint of job hunting, it is always better for you to have papers published in high-impact-factor Journals. You will be more competitive in the market. For examples, 3 papers from prestigious Journals such as Cell, Nature and Science might help you to land a job much quicker and easier than you have 10 low-impact mediocre papers. Besides, most employers are looking for talents in the field who can carry out 'most advanced or breakthrough' technologies, and usually those breakthrough technologies are published on top Journals.
When I saw your question, it reminds me of my old academic advisor who used to ask me the same question: "Do you want 2 'pennies' or do you want 1 'dollar'"?. He wanted me to publish on high-impact scholar Journals. In the viewpoint of job hunting, it is always better for you to have papers published in high-impact-factor Journals. You will be more competitive in the market. For examples, 3 papers from prestigious Journals such as Cell, Nature and Science might help you to land a job much quicker and easier than you have 10 low-impact mediocre papers. Besides, most employers are looking for talents in the field who can carry out 'most advanced or breakthrough' technologies, and usually those breakthrough technologies are published on top Journals.
I am agree with Yau, on the other hand contribution of two papers will cover certainly a bigger findings and data, which could also be of great help in generating knowledge
In case of original research, if you can split the works properly into two halves without affecting any of the works, perhaps you can try for two. For instance one of your research is from genetics and the other one is pharmacological or immunology based; you can easily split into two at least and submit in two different journals (one associated with genetics another with pharmacology or immunology). If you can not separate them properly, better not to divide for publication purpose, because in those cases even publishing one would be difficult.