1) Sikorski is able to make things work, and accepts a kind of Finlandization to keep Poland free. Its foreign policy is constrained, but internally Poland is able to make its own decisions.
2) Sikorski tries to balance everything, but fails. Communist coup takes place (either internal or external), and we have the Poland of OTL, but probably with even more of a history of trouble.
3) Sikorski tried to balance everything, but fails. Attempted Communist coup sparks WWIII.
So the most likely scenario is still one where a puppet Communist regime is established. However, there remains an outside change that Poland might become an even more compromised Finland, that retains its own domestic destiny. This has massive impacts in how the Cold War will happen - and if anything like NATO or the Warsaw Pact develops. It's possible that Stalin will have his own empire in the Balkans, but there is a border of neutral states (Poland, Czechoslovakia, Austria) between the Western democracies and him.