Lots of people use the TW200 with no problem; it's a solid design.
I prefer the OEM style myself, mainly because I've never had an issue with vacuum driven petcocks, but there is no problems with the TW200 style either.
Did the TW200 valve have a rubber gasket? Did it potentially get unseated during install? Maybe add a washer or 2 on the screws in case they're bottoming out and not tightening the petcock all the way down?
1986 Kawasaki Vulcan 750
NGK Iridium Plugs #7803/DPR7EIX-9
Duralast Gold ETX15 AGM Battery
Coastered & Shaved
Metzeler ME880 [110/90-19, 170/80-15]
Balance Dampers Replaced
Rebuilt Forks w/ Progressive Springs
VN750.com Grill Cover
Emgo 23-92411 Handlebars
MOSFET FH012AA R/R
1990 Kawasaki Vulcan 750
1998 Honda VFR800 FI
2014 Honda VFR800F
1989 Pontiac Firebird Formula 350