I have a 15 gallon fish r fun hex and i think it is fine. the filter is not brilliant but i have added another filter so the original filter is just for back up.
the lighting is not to bad, i have successfully grown vallis, amazon sword and two other plants which i was unable to grow in my jewel tank with upgraded lighting.
the only thing i dont like about the tank is the fact that it is all in one plug, cause you cant use a light timer as when it turns the lights off the filter and heater will be turned off but thats just the lazy boy in me coming out.
i bought the tank, stand, food supply, water treatment chemicals, another filter, heater, moon lighting, fully stocked it, fully planted it and added wood and gravel and pots for way cheaper than my jewel of the same size. and to be honest i find it a better tank and a hell of a lot nicer to look at.
the tank quality is ok and strong, the hood will need modifying if you want to add new heaters or filters but it is easy.