In China market, normally the heavy type stainless steel ball valve are from North factories, the compact type are mostly made by south plants. So if you more care about the price and have lower budge, then you can consider the compact type ball valve, in short time there is no much differences between heavy type and compact type, but maybe 5-6 years later then you can find that the compact stainless steel ball valve need to be replaced by a new one, while the heavy ball valve are still good enough to performance its all functions in your plumbing. Meanwhile I suggest customers to buy the stainless steel ball valvefrom a big factory. Even some small mills can also make stainless steel ball valve, but most of theirs finished product more or less will have some flaws, for example there is no deburring & shot blasting treatments or their treatment is not strict, their polishing is rough(not ideal). more over the size of final castings can not be correspond with their drawings.