It looks like it's completely inferior to the Tiger II (at least the Henschel variant used for production). It had 100-140 mm of maximum frontal armor depending on the variant being considered, and the Tiger II had 150 mm of sloped frontal armor on the glacis, and 180 mm of armor on the turret. In terms of firepower, the Tiger II mounted the same 88 mm KwK 43 as the post-redesign Lowe, and it could take the 10.5 cm cannon used by the pre-redesign Lowe, as evidenced by several proposals to up-gun the tank to 10.5 cm. In terms of mobility, the variants weighed between 76 and 90 tonnes, much more than the Tiger II, while using the same engine, giving lower mobility in all areas. Its only advantage over the Tiger II seems to be that its side armor was 100 mm rather than 80.
It seems to me that the Lowe was badly designed the same way the Porsche turret was for the Tiger II. The large, rounded turret front made it inefficient in distributing armor (not to mention expensive), and made it much heavier. In fact, when comparing the tank to the Tiger II Porsche variant, it actually has heavier armor to show for its weight, but that's a moot point since the OTL Tiger II outclassed both of them anyway. If you want a 10.5 cm gun-armed tank, up-gunning the Tiger II earlier would be a much better choice. I think the only reason it wasn't done OTL was because it would reduce the rate of fire and round stowage, while the 88 didn't have trouble penetrating targets that would justify a bigger gun in the first place.