Looks cool! The number of data sources is surprising, and the pencil background looks amazing (does what it should, stay in the background).<p>However, what's the performance with big datasets?<p>For instance, I have a 2MM-records dataset which I can comfortably use in QGIS. BIME offers some great background maps, but I can imagine several huge bottlenecks from bandwidth (700mb files), browser limitations, etc.<p>How far can you pushed it?