Just sharing my opinion on GU10 (mains voltage) and MR16 (low voltage) halogen lights:
Despite the identical appearance (different fixings) of these 2 bulbs, I realised that GU10 casts an uglier light pattern than the MR16, the latter gives a smooth gradation from bright to edge, while the GU10 pattern shows the shape of the element, definitely not a smooth pattern at all - avoid!!
colourblind