Yes, cheaper, especially if you get your VAT refunded. I found almost all high end designers stuff were slightly cheaper in Italy, and way the hell more expensive in London. The Miu Miu leather Coffer was about 960 EU. With VAT refund it will come to about 820 EU, which translates to about $1100.
This bag was 670 EU. With VAT refund it came to 575 EU. Not a bad deal!
You pay a premium in London though. I thought I could find deals on UK based designers, like Jimmy Choo, but no luck there either. The Dollar is so weak against the pound that it's not worthwhile. Also things just cost more there. I bought a Max & CO coat in Florence for 289 EU. That exact same coat in London was 279 pounds. Way more expensive in London.