There are many variables and usage patters that will determine which VM size is best for your needs. A DS2 may be enough for some workloads but for example if you want to train Deep Learning models on GPUs you will need to use a NC6, NC12, NC24 or NC24r
(NCv2 as well) machines. If you share some insights on the kind of work you are doing, it will be easier for us to comment. The best way to use the VM will also depend on these usage parameters and scenarios.