As above I use my Evo Rage , generally I tend to mitre them at home rather than take the Rage to work. Funnily enough I've just done a house over the last couple of days using metal trim. I loaded it out Weds afternoon , and counted how many mitres there were and just mitred both ends of 6 lengths weds night. Just a case of cutting to length on site then with a junior hacksaw ( the internals are cut square ).
I also keep a set of templates ( 3 pieces ) for the 2 tile splashbacks in the WCs for this particular builder , its always the same ( portrait - porcelanosa 333 x 200 ) and cut a set at home for each new plot. No messing about then , 2 tiles on , slide in the ready made trim set . :0)
Diggy