For the record, Alpha 5 (atm at 5.17) is up, and running quite stable,
Ray Fowler is releasing the updates for reported bugs very fast.
Tactical combat is integrated, afaik some graphics are not yet final
and the game may also need some minor adjustments,
but i can honestly recommend it not only for playtesting purposes but also in general,
because regarding in what development state big companies usually sell games,
the current RotP alpha should be rated as medium to late beta.