People will harp on about just the tick in the box, but if prior to interview you have to shell out £500 for some sim lessons on type anyway, it's 6 of 1 and half a dozen of the other. You'll end up paying either way
This is very true. If it's a jet airline job your after, then you are going to need to get very familiar with handling a jet, which takes a bit of time, sweat and practice. At a sim test they will most likely want to see a combination of basic hand flying skills, basic instrument skills, and CRM. Without at least an insight into the speeds and new handling characteristics of the jet sim you will likely find yourself consumed by just one task. The MCC in a jet sim environment will therefore be good first experience, but one on which you will need to build, and to keep refreshing prior to interview. If it's not going to cost too much more then go to a jet sim. Did mine at European in Bournemouth some time back. Clockwork and old but it did the job of making me see the difference between jet and piston.
And yes it is just a tick in the box as well.