Boot space is compromised depending on the size of the tank. So you either go for range or space. If I were to do it again I'd modify the boot floor to fit a large toroidal tank in and have more boot space but that's an increased cost.
Unless you are in it for the long run or use the car for a decent level of business miles, (mileage allowance), then it's perhaps of questionable financial investment.
I converted mine because we had a company grant scheme about 5yrs back which meant it cost me £450 to convert it and due to mileage allowance, I broke even in 6weeks making it a no-brainer.
For me, the savings mean the car pays for itself every year in terms of tax, insurance, mot, tyres and servicing and gives me a hefty saving on any personal mileage. It's an old car now but one I will find hard to pass on when the time comes...