My brother bought one last year, the Kim Thayil sig. It's a nice guitar. Feels bulkier, heavier than a SG though, slightly different. It maybe a figment of my imagination. It's well balanced, not neck-heavy, which is great.
If you just want the Polara because of the differences from an SG or the Kim Thayil association I can get that. But if you want something that scratches the SG itch then just get an SG. There are plenty used out there for really good prices. New ones come up open box/demo for cheap too.
Otoh I've bought two mid level Guild guitars, and both sound and play great. I really love my X-175 Manhattan with the Dynasonics and Guildsby. It sounds especially gorgeous clean with some reverb, tape delay, or both.
I have no experience with the newer versions made overseas, but if you can find a 90s USA RI you can’t go wrong.
I traded a standard SG for mine back in 1997.
Everything about it was just felt better. Thicker body, no neck dive, a little more tonal options with the phase switch.
The only issue was the small frets. I got a refret done about ten years ago to medium jumbo wires and it made a huge difference in terms of clarity and overall playability.