If you create an account on PlugShare, it will let you "add a vehicle" in the upper right corner and will then default to the correct charging plugs that vehicle supports.

Assuming you are renting in the US (Europe is different), if you need to do a manual search or make manual adjustments, here's what each supports:

Tesla:

• Tesla (fast) (for fast charging)
• Tesla (slow)
• J1772 (if your rental comes with the adapter--most do, but look in the trunk and frunk for one before leaving the lot--often, it's in a zippered bag along with a wall cord)
• Wall (if your rental comes with the adapter cord--less common, and not a big deal since 120V wall charging is so slow as to almost be useless)

Polestar (and most other non-Tesla EVs):

• CCS/SAE (for fast charging)
• J1772 (no adapter needed)
• Wall (if your rental comes with the adapter cord--less common, and not a big deal since 120V wall charging is so slow as to almost be useless)

If you own your own EV, you can purchase a few extra adapters that expand your ability to charge (e.g. NEMA 14-50 adapter, like what you'd plug an electric clothes dryer or a 50-amp RV into, or a Tesla-CCS adapter if you have a newer Tesla and want to charge at CCS chargers), but rentals won't come with those (though notquiteaff mentions bringing his own personal adapter).

The other big difference to be aware of is that the Tesla fast charging network just works--you plug your car in and boom, it starts charging (and Hertz bills you at return). With CCS chargers, it's a mishmash of credit card readers (which may or may not work) and apps (which may or may not require accounts and may use geolocation, QR codes, or NFC tapping to activate the charger).

Personally, my recommendation is that if you are some combination of technically inclined, tolerant of potential frustration, interested in or educated about EVs, or have rented EVs before, then renting a non-Tesla could work out fine. If you aren't, though, then I would suggest your first rental experience be a Tesla, and hold off trying a CCS EV until at least your second rental. (The one caveat to that is that the Tesla moves a lot of the controls that would normally have dedicated buttons or stalks to the central touchscreen; I found it very intuitive and easy to use, but others have complained. The Polestar and other EVs are more traditional in that respect, but IMO, the tradeoff in charging infrastructure still makes the Tesla the better initial EV experience for the uninitiated.)

This is probably somewhat subjective. Personally, I would say that the Polestar is slightly more comfortable and feels like a more solidly-built car (unsurprisingly, it has a bit of a Volvo feel). The interior feels slightly smaller, though, so if you are a larger/taller individual, then you may find it less comfortable. I personally find the Tesla to be perfectly comfortable, though the build quality is notoriously inconsistent, and my very first Model 3 rental had terribly harsh suspension that nearly turned some family members off of Teslas until I went back to the rental office and traded for another Tesla that had a much smoother ride.