I can't speak to the commissions or profit sharing, however for commercial I have found them generally expensive and difficult to deal with. Emails ignored, slow turnaround, etc. etc.
Kinda like that relatively attractive girl at the party who knows that guys want her phone number, so she just acts like a you-know-what.
Chubb is the gold standard but can be difficult to deal with. Another note: That niche can be less profitable than you may think. Premium on that $5m house compared to the $350k house.... vs service time required. YMMV, but it can be a rough market to work in.