First, there are literally dozens of mics that are "known for making many a famous & great acoustic guitar recording."
Second, which AKG 414 did he mean?
Third, if you actually do a careful test with level matching and similar positioning, I don't think you'll get less ambient noise and reflection from a dynamic compared to a condenser of the same pattern. The reason so many people believe that a dynamic works differently from a condenser is that they position them very differently.
Fourth, the Sennheiser is one of the most condenser like (flat extended frequency response) dynamics out there, but has very low sensitivity so it requires a preamp with lots of very clean gain so your budget must take that into account.
Fran