Ya, pretty much just personal preference.
The Butane does a really good job at getting all the good stuff without any of the bad in only one run, the IPA picks up a lot of undesirables and I typically do multiple runs in case I missed anything previously (if using IPA).
Butane is NON-POLAR, meaning the molecule doesn't have a negative and positive side because its equally charged all around due to its structure.
IPA is an alcohol and is neither non-polar or polar because it has parts that's act as each. (The hydroxide is polar (OH-) and the carbon portion is NON-POLAR or evenly charged) The reason you do the IPA washes so god-dam-cold is to freeze any water based particles or polar particles so they are not dissolved by the polar side of the IPA and water mixture. Water is a polar molecule.
The reason people freeze butane extractions is to freeze the waxes that make up the tric stalk and head that are non polar and will be dissolved with the butane (as well as butane is a gas at over 32°f so it has to be cold to "wash" with it). Lipids and waxes freeze at warmer temps than canabinoids.
If you want all the good stuff in one run, butane's your girl, but IPA can be just as good and none of the outdoor BS. If you got lots of material IPA the cheaper route, so its just all personal, IMO.