As others have said JJP is not a boutique pinball company.
JJP has a solid reputation at this point while the others do not. American Pinball needs to prove themselves with their first game. I won't ever consider buying a Heighway or DP game due to the support nightmare stories and past business practices of both companies.
Paying $8k-$10k for a game from companies that have support issues, take weeks (or never) to get back to customers and at times have not been transparent doesn't sound like a wise purchasing decision at this time.