Both CA and FL are members of the Interstate Compact which means they share information. Usually this means your DUIs in another state w/i 10 years will count against you in CA. This is not always the case however as it depends on how a DUI is defined in the state you are coming from. Some states do not require that you actually drive the vehicle while intoxicated; being in control of it is enough. For example if you pass out parked in your car in some states even though you were not driving you will pick up a DUI. CA requires actual movement of the car, even if only a millimeter. If your priors were based on convictions that would not be convictions under CA law they will not count against you.
Mr. Kaman is correct. Not all DUI convictions from other states count as a prior DUI in California. From my brief research on the issue, it sounds like a Florida conviction doesn't fit the requirements for a California "prior."
Fla. Stat. Section 316.193 defines drunk driving as when "the person is driving or in actual physical control of a vehicle and... under the influence of alcoholic beverages [or drugs] when affected to the extent that the person’s normal faculties are impaired," or has a blood or breath level over .08%.
Besides the fact that you can apparently get a DUI in Florida without actually driving (for instance, stumbling out of a bar drunk and climbing into the back seat with your keys in your pocket), the definition of impairment is different enough from California's that I don't think it equals a California DUI prior.
Of course, that's just from five minutes of looking at some Florida statutes. If I represented a client in your position, I would do more research on Florida law, and consult with a Florida DUI attorney, before coming to a firm conclusion.
Just be careful when you hire a DUI attorney, and don't accept an answer from a lawyer who apparently believes you can always be convicted of a third DUI in California based on out of state priors.
To sum up the discussion of the other attorneys, for the FL cases to be priorable it must meet the same requirements of the CA vehicle Code sections VC23152(a) and/or VC23152(b) and applicable case law. A few years ago, the law changed in CA and went from 7 years to 10 year for a DUI case to be priorable.
I recommend getting a certified copy of the minutes of the Court or a Docket Sheet in FL for a DUI attorney's review.