I will insist that the man-hours matter. You mentioned Common Lisp: it's a good example. I found bugs and limitations in CL runtimes and was several times in a

I will insist that the man-hours matter. You mentioned Common Lisp: it's a good example. I found bugs and limitations in CL runtimes and was several times in a situation where it was clear that I was the "only user". I do not want to be in that situation. BTW, CL people often say that one should get a paid Lisp because of support. I did (AllegroCL) — and Franz people were really nice, but couldn't find the problem, and I couldn't dedicate the time to hunting it down and providing debugging information. Support doesn't mean that your bugs get fixed. The JVM is not perfect, but its usage scale matters and means that in general, you are not likely to hit a JVM bug.