I have always found this a funny subject fraught with 'what' and 'what not' to do's. From a 'Newbee' perspective I think it can become deeply anguishing! If you find out that you have a Sim assessment on a jet and have absolutely no experience of jet handling, it has often been said to me that you cannot really afford not to purchase some pre-sim ride experience. I think having a general feel for things before hand may prove invaluable. You hopefully will be shown what to look for, where and when to make the calls and what you should generally be doing when you are both PF and PNF. Surely having a head start on this can only be of an advantage? The only downside is the cost; especially if unsuccessful. However I'd rather be unsuccesful knowing that I had explored all areas before hand, instead of wondering 'what if' afterwards.