Great when things run smooth or ......
I am a real fan of Lastminute.com, especially secret hotels. The cashback rates are very good and nearly always track and pays out quickly.
Only issue is if anything goes wrong, Lastminute.com are renowned for their poor customer service - which includes shouting at customers, patronising and refusing to escalate calls. I have not been subject to this previously but have finally had to face customer services when I needed payment confirmation (not much to ask) - it was worse than I ever expected.
In essence - as long as you do not need to speak to them or query anything - they are brilliant and I would recommend.