A couple of years ago I had a Studio license at Stencyl. I really like working with their blocks to create things, it's great to use and a lot of fun. That for me is a big plus. But there are too many drawbacks. Having not visited their site for a long time after I stopped using Stencyl (because I'd stopped developing any games so I wasn't using any program) I recently revisited it and was surprised to see it hasn't seemed to have moved on at all. It's no exaggeration to say it's been very slow to progress. If you go on their roadmap page it still says their version 3.5 is "coming late 2017", as I write this it's now middle of April 2018 and they've not even bothered to update that page to say the release is delayed and give a new date.
Compared to Construct they don't support as many export options and the support on the forum isn't as forthcoming simply because there aren't as many members. There are some really nice people that use Stencyl and will help out but the number of them is low. The number of people working on Stencyl to develop it is also low, hence the snails pace of their development.
As much as I do like Stencyl and enjoyed using it, at this time I'd only recommend Construct 3. Unless Stencyl suddenly comes out with a huge update and gets a tonne of people onboard developing it then looking to the future it's only likely to fall further back.