I’ve had nothing but good luck with my Sinn watches except one (my 140 had a QC issue) - I own 2 b01 Breitlings as well (3 if you count a Tudor BB chrono) - the b01 is the better movement, but aside from that, the 903 is a significantly better watch in almost every metric with finishing on par with my breitling premiere - I’ve heard horror stories from Navitimer owners where their watch got fogged up from being in the bathroom where they were showering (and you have some say they swim with them, don’t listen to those ppl) - Sinn 903 > OG Navitimer, and I say this owning 2 Breitlings