I have just completed the grad programme at Deloitte. I joined after a masters and 2 years work experience with the result that I'm a couple of years older than average. I have seen a few people join recently as experienced hires with little more experience than I had. If you go through the consulting grad programme you have a lot of training and support, and the opportunity to really build up your consulting skills. I have seen this lacking in a couple of the experience hires who came in from industry, and they have struggled to keep up with their peers who had completed the grad programme. On the other hand they are two years "ahead" of me and started on a salary up to 20% higher. If you have built up strong powerpoint, excel, and project management skills, and have a good understanding of business transformation and managing change, then you should be ok to apply as an experienced hire at Consultant level. If not, go for the grad programme. Hope that helps.
