Waves has his own format for impulse responses - wir, but you can import wav files and get the responses from them. The free format for responses is wav, of course There are many resourses in internet when you can get impulse responses.
But Craig said something else - that in Samplitude all these goodies are INSIDE the software, for no additional cost!! Room simulator, FFT noise reduction, multiband compressor - all is there. Waves now have IR, but this year, and for a lot of money. Samplitude have convolution processor 5 years ago, and inside the software. They were the first who built a multiband compressor-expander in a native software.
I,m not selling Samplitude , but it's great.