Both of those designs are sealed and good subs. However, sealed subs are costly and not optimal. They are always brute force designs, requiring massive drivers and powerful amplification which adds to cost. The only reason for designing and building a sealed sub is a small foot print and form factor. There is absolutely no other advantage.
Don't get hung up on group delay. There is a lot of nonsense about this. It has to be greater then 30 m/sec to be audible, and that almost never occurs in any sub. So that is essentially an irrelevant spec.
The point of this being, if you have room, you can get as good or better results, at far less cost selecting a good ported sub. To put it bluntly, the whole concept of a sealed sub is awful from an engineering standpoint and would not be considered if not for aesthetics.