Mr. Cool Gen 5 comparison and questions

For people who don't want to spend 15k to heat and cool a small space, these DIY systems are a popular option, so for the people (like myself) who are considered one of these, which one is the better pick?

From what I can see, Gen 5's more efficient (20 vs 23.6 SEER), it's using the new R-454B refrigerant, and quite a bit more expensive.

I did not find any info regarding the Gen 5 Mr. Cool system, not have I found it advertised on their site or Home Depot, but Lowe's has it.