I have a tuning box currently fitted, set to a low setting.
Unless you're willing to pay for a digital box (over £100) then you very likely get a an analogue box.
A digital box has a a microcontroller in it which _might_ have mapping to control the effect. A sensitive microcontroller can derive rpm, injection timing and rail pressure just by monitoring the rail pressure.
Analaogue boxes tend not to have _any_ mapping, but instead have an adjustment potentiometer on them to allow you to adjust the gain of the signal amplifier.
My box was advertised as digital, but is in fact analogue. I have seen two other 'digital' boxes since getting it and they have also been analogue, one of them was the Italian box. I didn't even try the Italian box because they sent me the wrong cable and so I returned it for a refund, once I discovered that it was an analogue box (by using a dual trace oscilloscope and comparing it's behaviour to another known analoue box). Having said that, the Italian box is probably still one of the better analogue boxes and seems to be a similar circuit to the one I have.
I have joined a small group of developers in an Indian web forum who are working at producing an open source (free, in other words) digital and fully mappable tuning box.
The cost differential for the components between a digital and an analogue box is small, only about 20% more for digital. A typical analogue box, based on a common twin LM324 op amp design has about £3 of electronic components, £1 for the pcb, and £3-£5 for the box and interfacing cables to connect it to the engine.
A typical digital box has about the same costs as for the analgue box, except for an additional £2-£3 for the microcontroller.
A good digital box could be developed which allows the user to produce their own maps simply on their PC, and then load them onto the box either through a USB plug or an SD memory card.
At the moment, because analogue boxes are still high profit devices, digital boxes are priced to be even more highly profitable, just because they're digital. Having said that, just because it might be a digital box, a digital box isn't necessarily good just because it is digital, because anyone with a little bit of determination can program a microcontroller these days.
I'm leaving my analogue box on because at it's lower settings it does the job quite well of bringing up the low down torque, which suits me and my drilled dpf. At higher settings, above 6 (out of 10) it gets a bit choppy and at low revs, when you're trickling through a carpark slowly for example, the higher fuel pressure boost at low revs (all still within safe limits) can feel a bit bumpy.
Best bet is to try one and see if it suits your needs. Or send it back for a refund