I like how easy it was to set up with my existing postgresql server setup (with raster data). The performance of this solution has been exceptional compared to any previous solutions we have used over many years running our business applications on topographic maps - which are stored using GeoJSON or WKB files rather than traditional shapefiles! We had hoped that there would some way to use ESRI's ArcObjects API but so far no luck from what i can see here. A more flexible approach could potentially solve problems where you don't want all your users accessing every layer at once though perhaps if they need access across multiple layers then having them load one map per user might still work better? At least give consideration before dismissing out right an option because its not exactly "Arc". Our application uses Esri basemap tiles along side custom tiled imagery created by us when available eg satellite images etc.