Actually, having been TA and now in the regular Army, I think the biggest difference between the TA and the Regs is the officers. You could take any TA soldier I know and, with a bit of training, get him to fit in with a regular unit no problems. Trouble is, the gulf between regular officers and TA officers is vast and unbridgable - how could it not be? We get a year of 14 hour days training, TA officers get something like (off the top of my head) 12 weekends and two three-week courses. I'd say that was the TA's biggest weakness in terms of working with the regular Army.