Take a deep breath. I know how you feel, I was a 787 only flyer till I tried the pmdg 737(was honestly very afraid as it’s a really detailed aircraft, more worried about the performance aspect) but it blew me away, out of the sky! In fact sometime later today they’ll be shipping out an update for performance optimisation and some handling improvements to the AFDS for the PMDG 737.
My honest thoughts for a widebody long hauler? Wait for the pmdg 777, it’s said to have an even better performance than the 737. Worth the wait, but I’ll take a complete and polished product and enjoy simming without worrying about performance and stuttering etc. Not that I’m bashing the updated 787-10, it’s great with the new EFB and simbrief/navigraph uplinks which works amazingly well and takes less than 5 seconds to connect to your account with just your Pilot ID on simbrief, but I just wish they could match the fps which the PMDG 737 accomplishes without raising a finger.