no it does not pull a deep vacume.proper evac of an ac system is 250-500 microns.1000 microns will do if in a hurry.but 28" is not even close.you will not get all the noncondensibles out with a 28" vacume.moisture can mix with oil,especialy mineral oil (kinda like it does with brake fluid) and it will not b oil out at high vac. levels.
No I have not tried one and dont think I would unless there was no other option.I see vacume pumps in pawn shops for 40-100 bucks,thats a realprofesional type pump rated at 4-8 cfm.
Also the HF vac pump I saw said it was rated at 14 " vac.Either way 14-28" is not low enough to get moisture and noncondensibles out of the system.I have seen what lack of vac can do to systems in the long run so Im not going to try it on my stuff
On the other hand if you use it and you like it and it suits your needs more power to you. <img src="/forums/images/graemlins/cheers.gif" alt="" />