We have an IR "commerical" 5 zone oven with about 1.6m of active reflow, it does OK with plastic connectors (white ones certainly go a tiny bit browner). However advice and papers you might find out there suggesting IR is better than convection because it is efficient etc, no longer apply to modern electronics. We surface mount things these days that just do not suit, connectors, tall electrolytic capacitors (shadows), big inductors, big boards, component density, all of these things exaggerate IRs weaknesses. Modern convection oven don't have these issues, however the bigger and more expensive ones will handle bigger denser things better, I suspect a benchtop £5-15k convection oven for instance probably still struggles with big inductors on a dense power board or ceramic PCBs.