It's clearly in Ontario's interest to move to the VAT to eliminate the inefficiencies associated with the fact that the current retail sales tax in Ontario taxes business inputs substantially. The question is how to do that.
There are two options you could pursue. One is to have Ontario do it unilaterally by adopting a Quebec-type system, a QST-type system--well, there are three ways of doing it. One is to harmonize the retail sales tax to the GST at the retail sales level just by including services, but you'd run into the same problem there as you would with the existing tax. Another possibility is having Ontario adopt the QST; then you'd have three separate provincial GST systems, which starts to become unwieldy for businesses dealing in many provinces. The only workable option, it seems to me, is for Ontario to harmonize with the federal GST by effectively joining the HST.