I have one and it is way better than a hand held in my opinion. I did a pass with the diablo stock tune and then took it off and put a chip in and i gained 8 hp to the tire without any modifications to the chip. its great. hand helds are more convenient though
you didnt gain 8HP based on the media in which your tune was stored(handheld to chip). the gain was made with a superior tune on the chip. This does not make the chip better than the handheld it only means that the chip contained a better tune. for just about everyones application chips are senseless. they are difficult to have reprogrammed and have none of the benefits of a handheld tuner. handhelds allow for datalog, chips do not. handhelds allow for convenient personal adjustments, chips do not. etc etc etc. Look into a reputable shop that you want to do your tuning before you do anything else. Decide who will be doing your tuning and then asked said tuner what he/she uses as far as software goes. most places use SCT who, in my opinion, make the best products tuner wise. If that is the case go with an SCT handheld. If the shop says they use Diablosport then get diablosport. Its not the handheld or the chip that will help you, its the guy who does your tuning. Just get the handheld for simplicity.
If you have the money id recommend the SCT livewire or even their new touchscreen tuner. both are extremely nice, allow for all the extra adjustments and simplicity, but have some extra bells and whistles to go with it. If you wanna save cash SCT's Xcal3 is great.