  Two models incorporating different forms of spontaneously broken quark-lepton
symmetry are discussed. Both models are constructed so that quark-lepton
symmetry can be broken at as low an energy scale as phenomenology allows, thus
maximising their testability. The first model uses the Pati-Salam gauge group
SU(4)$\otimes$SU(2)$_L\otimes$SU(2)$_R$. The main analysis presented here
concerns large threshold corrections to the $m_b = m_{\tau}$ tree-level mass
relation. The second model is a new and simplified theory using discrete
quark-lepton symmetry which has a very economical Higgs sector and elegantly
avoids a potential quark-lepton mass relation problem.
