If you've reached the point where you're comparing the Lelit Bianca V3 (~£2,200) and the Profitec Pro 600 (~£1,800), you already know what you want: a dual boiler with flow control. The question isn't whether to spend this kind of money — you've made peace with that — it's which machine does the job better.
A rotary pump. The Bianca uses a rotary pump; the Pro 600 uses a vibration pump. In practical terms, the rotary pump is near-silent (your grinder is louder), can be plumbed directly into your water supply, and delivers smoother pressure. The vibration pump on the Pro 600 is perfectly capable but audibly louder and can't be plumbed in.
The aesthetic. Let's be honest. The Bianca is one of the most beautiful home espresso machines ever made. Walnut wood knobs, lever, paddle, and feet. Dual manometers. The flow control paddle sitting atop the E61 group. It's a machine that makes people stop and ask about it. The Pro 600 is handsome in a "German engineering" way, but it's not going to be on anyone's Instagram.
An electronic low-flow mode. The Bianca V3 added a mode that simulates flow profiling electronically, so you can set a profile and let the machine execute it without manually moving the paddle. The Pro 600's flow control is manual only.
£400 in your pocket. That's not nothing. That's a Niche Zero. The Pro 600 with flow control is a complete flow-profiling dual boiler for £1,800 — £400 less than the Bianca. If the rotary pump and the walnut wood aren't worth £400 to you, the Pro 600 is the rational choice.
Faster heat-up. The Pro 600's smaller boilers reach temperature faster than the Bianca. In daily use, this means less waiting in the morning. Both machines benefit from a smart plug on a timer, but if you're switching on and waiting, the Pro 600 wins.
German manufacturing tolerances. Profitec's build quality is exceptional. Everything is precisely machined, every gasket seats perfectly, every fitting is the right grade of stainless steel. The Bianca is beautifully built too — this isn't a knock on Lelit — but Profitec's engineering precision is a notch above.
Buy the Bianca V3 if: the rotary pump matters to you (quiet operation, plumbing option), you want the most beautiful machine in the category, or you value the electronic low-flow mode for hands-off profiling.
Buy the Profitec Pro 600 if: you want to save £400 without meaningfully sacrificing espresso quality, you prefer German precision over Italian flair, or you'd rather spend the savings on a better grinder.
Both machines will make world-class espresso. Both will last 15+ years. Both will be the last machine most people ever need to buy. The Bianca is the one you fall in love with. The Pro 600 is the one your engineer friend would choose.