Is it plagiarism (or bad practice) to cite reviews instead of source material directly? My first source of information when preparing a manuscript are reviews. If up-to-date and comprehensive, I feel I can create most of my introduction by rephrasing and citing them. Nevertheless, reviews are based on citing other papers and, with the deluge of literature published these days, finding the source material for a single claim sometimes becomes a never-ending and time consuming play with a Matryoshka doll.

For example, in this review by Misteli (2007), the following claim is made and supported citing three papers.


  The recent development of methods to probe the physical association of
  genome regions in a unbiased and genome-wide scale should lead to
  rapid progress in our still-rudimentary understanding of the
  functional significance of chromatin loops (Simonis et al., 2006;
  Wurtele and Chartrand, 2006;Zhao et al., 2006).


I consider relevant to a point in my article that there are new roads being opened to study “the functional significance of chromatin loops”, To do so, I have three options: 


Rephrase the sentence and cite Misteli, 2007, acknowledging that I extracted the citation from the review and depriving the authors of the source material of a citation;
Rephrase the sentence and cite Simonis et al., 2006; Wurtele and Chartrand, 2006;Zhao et al., 2006  without reading the three source papers, which is kind of deceiving but at least acknowledges the authors of the research and not the author of the review; or 
Read the original articles, rephrase and cite Simonis et al., 2006; Wurtele and Chartrand, 2006;Zhao et al., 2006, which is the most “honest” option but incredibly time consuming.


Sometimes, if I decide to do 3, I may find myself spending a lot of time reading, only to write something that was already said in the review. 

Which option you would abide for? Am I somehow plagiarising the reviewers or primary authors if using any of my strategies? In terms of ethics and good scientific conduct, which is the best option? How deep and when should I look for source material?

I am not asking about which version of an article to cite, like here. I assume that versions cited in reviews are the most up to date. I am asking when it is correct to cite the review or the primary source found in such review.

Note: My strategy up to this days is a mix of 1 and 3: search and cite the source material only if the paper is relevant for the core of my article and cite the review when filling the generals.
Yes and No.

A review is not (or at least should not be) just a list of papers in the field, it is a research paper in its own right. A review should provide some form of new structure or idea that come from reviewing the scientific output the field in question. Thus a review can be useful when either pointing at the results emerging from the review or when you wish to provide an example of where a throrough description of a field is provided. So citing a review should primaruily be for general purposes. 

If you need to cite a specific detail provided by one or several references in the review you should turn to the cited articles and check them. There is, first of all, no guarantee that the citations are correct and citing something that is not correct propagates errors in publications. In addition, the cited work may not be all the relevant work supporting a point from your perspective so your sources may become biased. After all your point for writing is most likely not the same as for the one writing the review.

A review therefore has a function on its own for providing overview and synthesis which can be cited but if you need to cite details you must go to the original work and also not limit yourself to the reference list of the review.

EDIT: Just to answer the question in full: plagiarism is only if you copy the text with out quotes. If you copy the references you are not necessarily plagiarizing but you will then give the false impression that you have actually read, in part of fully, the articles concerned and that is in the realm of unethical behaviour. In the best case, it is unwise for the resons given above.