The ease of use, how quickly you can get up to speed using this product in your development environment without much effort or setup required! It's also very easy expand upon what it does as more features are added via plugin modules that help automate tasks such as data collection from databases/web services etc..
I would really like if there was some way where we could create our own custom metrics rather than only having predefined ones available but overall its been great so far - just be careful when integrating into any existing build pipeline systems since they tend not have builtin support yet for gatlings capabilities which means extra work needed upfront before getting started otherwise everything works well outof box once configured correctly :) We've used GATLING primarily during initial phases after deployment by setting thresholds at various stages along different aspects within application life cycle e.g., number requests per second received / accepted vs time spent waiting; average response times across all endpoints compared against.