Have you investigated the comparison tool on the Health Insurance Authority website ([broken link removed] You could use it, for example, to compare the Health Plus Extra plan to any other available plan, whether with VHI or another provider. Or you could use it to search for suitable plans by inputting the criteria that apply to you and your preferences.
Just as an aside, I don't think the Health Plus Extra plan has any excess. You could reduce premiums significantly if you are prepared to accept an excess, eg, Health Plus Access or Health Access, also from VHI.