I did my XL type in Dallas about a year ago and have also done many sessions in the sim as one of their rightseaters. Its a basic XL sim with Primus1000 avionics and dual FMS. Gets the job done and rarely breaks down.
In regards to the instructors it really is a crapshot, as with any training. Some instructors are good, some are less good.
If it's significantly cheaper than in the UK I see no reason not to go to Dallas. Remember, despite higher cost to get here you may make that back in lower hotel and meal costs.
FYI, I have never been to Burgess Hill so can't make a comparison between the two.
And you get to go to BoneDaddy's.
