The DCT transmission should not give you any issues, if you handle it respectfully, and the engine knock I have never heard about. The Alsvin is a decent car and maintenance is like all other cars. Changan is doing rather well so dealership support should have you covered too in terms of spare parts.
I'm not too sure what the resale will be like but I cannot imagine it being too bad, it definitely won't be as good as a yaris or a city but 4 to 5 years is a long time and I think you would get your value out of it. I personally would would recommend to buy a used corolla altis instead. If you have your heart set on an Alsvin I would probably buy a used one, if there are decent options!