The spin-triplet superconductor UTe2 has recently emerged as a rich system that incorporates aspects of unconventional superconductivity, heavy-electron physics and non-trivial topologies. Superconductivity in UTe2 is characterized by enormous upper critical fields that exceed the paramagnetic limit and re-enter in ultra-high fields, nodal quasiparticle excitations, chiral in-gap surface states, and multiple distinct superconducting phases that span regimes of temperature, magnetic field and applied pressure. Superconductivity emerges from a renormalized electronic structure of hybridized f-electrons which give rise to archetypal heavy fermion features such as an enhanced quasiparticle heat capacity and hybridization gap, yet key questions about the nature of magnetism, electronic structure, order instabilities and sample dependence remain. In particular, recent advances in crystal quality have been achieved by varying synthesis methods - including variations in techniques, composition and and even temperature ranges used for growth - to enable enhancements in conductivity, transition temperature and ability to measure quantum oscillations. This talk will review the evolution of sample variations and resultant physical properties of UTe2 that shed light on the nature of superconductivity in different parameter regimes, focusing on milliKelvin measurements of thermal conductivity as a function of temperature, magnetic field angle, and sample disorder.