Advice from a David Tomlinson lecture:
- one wheel (the weight put inside should be concentrated over the wheel).
- not a builder's wheelbarrow (viz wide and relatively shallow, not narrow and deep).
(for carrying bulk light things, like leaves, you can have a wooded frame that extends the sides of the wheelbarrow out).
Personally, I like plastic, for ease of lifting the wheelbarrow in and out of my van.
Find a good quality plastic wheelbarrow (on a metal frame, etc.) outlives many perennials.