I chose Nuova Locanda Belvedere as it was close to Mestre station and it was really good price. In only booked it week before my holiday, read the reviews which got me a bit worried but still decided to give it a go and I can honestly say, it was absolutely fine. Girl at reception desk was very helpful, room was ok, exactly what you would expect from a budget hotel. They have their little vending machines for coffee and snacks which for me were life savers.
They do accept cards and even though the machine didn't work when I arrived at the hotel, the staff were fine for me to pay the next morning.
The only thing that I could have done without is the noise. Nothing that could have been helped by hotel staff in any way. Some people think kick opening toilet door is acceptable.
Bathrooms even though shared, were clean.
I can honestly say, if you just need a roof over your head, somewhere close to public transport and don't mind shared bathrooms, Nuova Locanda Belvedere is your place to stay.