Open topped tanks allow a lot of water evaporation; they potentially allow airborne contamination to fall into the tank; and fish can easily jump out.
The night time setting on the first tanks seems to suggest that a blue light is left on all night. This is not good for fish, there must be a period of total darkness in every 24 hours.
The first tank has a bigger footprint than the Fluval, but the Fluval has a very slightly larger volume. However, they are both small and will limit what can be kept in them.