The NEC4.2 comparison in the answer below shows one example, for a practical set of installation conditions.
NEC4.2 comparison of an inverted V, center-fed dipole with a linear center-fed dipole:
- The apex angle in my plots here is mislabeled. The correct value is 120°.
- The graphic below compares the elevation pattern gains at 90° azimuth intervals for these two configurations; posted in response to the comment of rclocher3.