Are the later Personal Tesseracts added when I've got Bob's Equipment supposed to be worse than the mk 1? Although they have better efficiency, they have a lot less power throughput. Personally, I'd rather just make more power generation for my factory and spam the mk 1 due to the higher power density than use the mk 4.

All Personal Tesseracts require the same power from the global buffer. Higher tiers provide less efficiency and less individual power to the equipment grid, but are smaller (tier 1 is 4x4, tier 2 is 3x3, and so on) which actually provides a density that more than overcomes the reduced individual throughput.

In short, higher tiers are less efficient, smaller, and provide greater throughput per tile in your equipment grid. If for some reason you find otherwise, that's a bug on my end.