Material And Colour
Most of this is a genuine matter of taste. Two parts of it are not, and one of them is gauge.
Short answer
Aluminum in an adequate gauge is the right answer for almost every Toronto house. Gauge matters because ice load and ladder contact deform thin material. Colour is a free choice with one practical note: match the fascia capping rather than the roof, because that is what it sits against visually.
The materials
Aluminum: the standard. Does not rust, forms well on site for seamless runs, available in many colours, and the right answer for most houses.
Gauge within aluminum matters: a heavier gauge resists ice deformation and ladder damage and is worth the small premium in this climate.
Galvanized steel: stronger and heavier, and it rusts wherever the coating is damaged or cut. Used on commercial and where impact resistance matters.
Copper: expensive, extremely long-lived, develops a patina, and appropriate on a house where it suits the architecture.
Vinyl: not suitable in a Toronto winter. It embrittles and cracks and is a false economy.
And zinc, which is a specialist choice and is seen occasionally on heritage work.
Gauge is the one that matters
A thin-gauge trough looks identical on the day it goes up. After one winter of ice and one ladder, it is dented and slightly out of shape, which affects the slope and holds water. The gauge is a line on the quote and it is worth asking about specifically.
Colour
A genuine free choice — there is no performance difference between colours in any practical sense.
Match the fascia capping rather than the roof, because the trough sits directly against the capping and reads as part of it.
White is the default and is fine, and on a house with white trim it disappears.
A darker colour matched to the trim or the brick frequently looks better than white on an older Toronto house.
Dark colours show chalking and fading more over many years, which is worth knowing rather than avoiding.
And if the fascia is being capped at the same time, choose both together, which is the opportunity.
The details worth specifying
Trough profile, because the standard K-style and a half-round have different capacities and different looks.
Downspout size and profile, and whether round or rectangular.
Downspout position, because they are visible and the placement is a design decision as well as a functional one.
Whether elbows and extensions match the downspout colour, which is a small thing that looks wrong when it is missed.
End cap and corner quality, which on a cheap installation is where it looks homemade.
And the fascia capping colour and the soffit colour if those are part of the work, because that is the actual visual decision.
Common questions
What material should I use?
Aluminum in an adequate gauge for almost every Toronto house.
Is vinyl eavestrough an option?
No. It embrittles and cracks in the cold.
Should the colour match the roof?
Match the fascia capping instead. That is what it sits against.