I have two Aldi chainsaws, one two-stroke petrol and one electric. I've had them several years, I don't remember exactly how long.
I don't use a chain saw a great deal, but I've probably cut up around twenty tonnes of wood with them, typically twelve to fifteen inch rounds, and they've been absolutely fine.
I particularly like the electric one. I only bought it to see if it was any good because it was so cheap and I ended up using it more than the petrol one -- even when I've had to use two 50-metre extensions to get to the tree.
Oh - someone mentioned spares. I think the chains are bog-standard and easy to get, I think the carb on the petrol one is one of the Zuma or similar. I've never had to buy any spares.