Hi, I've noticed that the Wilcoxon rank-sum test is used by many R packages to calculate differential expression. Is this a good test to estimate that when you compare it to other packages like DESeq2 and edgeR which calculate differential expression with many more factors involved and would that not be better than just a Wilcoxon test? 
I agree with Devon here except I'd put the number even lower than 100 for trusting Wilcoxon. Rank based tests will find differences with sufficient power once you have, say dozens of cells with non-zero counts in each group that you want to compare.

We used Wilcoxon tests with Gibbs samples to also account for uncertainty from multimapping reads in Swish:

https://academic.oup.com/nar/article/47/18/e105/5542870

Jump to "scRNA-seq simulation" and "scRNA-seq of mouse neurons" for an examination of how Wilcoxon can be used effectively for comparing moderate-sized groups of cells (e.g. ~20 or higher) even in the presence of uncertainty from multi-mapping reads.