My company is medium size, at least within our industry, and I actively look for little companies. Every complex platform has bugs and un-considered edge-cases and poorly thought out engineering choices. Large companies don't fix them; small companies do. (That's overstated, obviously, but not wildly so.)

I'm the sort of client that wants to help you improve your product, and can - if you'll let me. When I'm allowed to talk directly to engineers (possible at small companies, vanishingly rare at large ones), we both end up better off.

I've seen the whole cycle, though, and it gets frustrating. Small and ambitious company works closely with me to build something really great; raises money / goes public / gets acquired; early employees cash out (good for them!) or get outsourced (disastrous choice); development stalls and features break. Now I'm back looking for a new small company to work with again. It's dispiriting, and so, so wasteful.