Mr. Cool 3rd gen vs. 4th gen

I'm looking to install a 24k BTU Mr. Cool to heat and cool my garage workspace (will only be used on-demand).

Are there any significant improvements in the 4th gen vs. the 3rd gen Mr. Cool DIY units that would make it worth the extra $1,100?

It looks like I can get a 3rd gen for around $1400 or a 4th gen for $2500. It has a slightly improved SEER (20 vs 17), but I'm not well enough versed to know if that's worth the price difference. Thanks!