If a sales trainer can make you buy him, then perhaps he really is good at his work. There are many sales consultants who speak a lot but know nothing about their work. They generally get their knowledge from books and journals and this knowledge is usually theoretical. However the best knowledge to have is the practical knowledge. If the sales trainer has a good experience at selling then he is anyway better than the one with theoretical knowledge. Communication skills are vital but experience counts more here.

A sales training consultancy would surely have experienced trainers with it. These trainers are reputed in their field and are skilled. They master the sales department whether it is theory or practical. But before you choose your sales trainer, make sure to ask him about his areas of expertise. If he is good in fewer areas then it is actually better. This is because he would then have an in-depth knowledge about those areas only. Quality is better than quantity. Fee of such consultants can be quite high but hiring them can be rewarding too. If you are not too sure about the person, you can ask him past clients about his work too. Maybe that would give a pretty clear idea about him.