We were(family of 4) flying from London to Hubli(Karnataka). So booked the spicejet flight from Mumbai to Hubli(SG2441 / B6FWTZ). Since SpiceJet website was not clear(saying how much weight they allow for International flights) I paid for 5KG extra per person.
At Mumbai airport I was told that for international travelers the allowance is 23KG and I was told that I will not get anything back from SpiceJet but I can re-use my excess payment while flying back to Mumbai as long as my international flight is within 24 hours from the domestic flight. I was OK with that.
I booked my return flight from Belgaum(Karnataka) to Mumbai(SG2452 / HE4TQE). As expected, we had more luggage than what we hoped to carry. Although I told the check-in counter person(at Belgaum) what I was told in Mumbai(i.e. I can re-use my excess luggage payment) but soon realised that there no such thing(i.e. principle & ethics) in SpiceJet world. So, I had to cough-up more money.
To top this all up, luggage loading/unloading people at SpiceJet made sure that the main handle of one of our bag has completely ripped off i.e. not usable! I complained this to SpiceJet counter(with photographs) at Mumbai Domestic airport on 5th Sept 2014 and no news yet!
On the positive side, I must admit, SpiceJet does maintain the time well. Flights are clean, crew members are brilliant and since I am a short person I cannot complain about the leg room:).
So, all in all mixed reviews. Paying money is not my problem. The problems are, ethics and attitude towards the customers(but not towards passengers. To clarify, once you board the aircraft you are a passenger till then you are customer).