VS 
To give you an idea of how the Tria laser hair removal system compares to the Silk’n Sensepil, I’ve compiled a list of categories to put them up against each other, head to head. Please note that the Silk’n described here is the newer model ‘Sensepil’ – which is FDA-cleared – not the original Silk’n.
COST:
Comparing the cost of the Tria and Silk’n Sensepil is not as easy as it seems, primarily because the Sensepil will likely require the purchase of extra parts. At $499, the Sensepil is priced almost $100 lower than the Tria ($595), but the Sensepil also requires you to purchase lamp cartridges (you get 1 on initial purchase) that are good for about 750 ‘shots’ each.
Each of these cartridges costs $49, and you may need up to 6 or 7 depending on how much hair you plan on removing. This could put the final cost of the Sensepil at around $800.
TREATMENT PERIOD:
The recommended Tria treatment period for ‘accelerated results’ (according to the Tria website) is 7 to 8 months total, with twice-monthly sessions in the first 3 months, and then once a month for 4 to 5 months after that.
The Sensepil, on the other hand, can be expected to take up to 18 to 24 months, or the completion of a full hair growth cycle, according to their website. Sessions should be done twice-monthly for the first 2 months, and based on hair re-growth after that.
SAFETY:
The Tria was the first FDA-cleared home laser hair removal system, primarily because it includes a sensor that makes sure the skin is not so dark that burning or scarring may occur. The Tria will not unlock if there is risk of skin damage.
The Silk’n Sensepil was FDA-cleared shortly after the Tria when it included a similar feature. Its approval by the FDA was largely dependent on the Sensepil’s unwillingness to activate on darker skin tones, thereby avoiding serious burning or scarring.
SESSION SPEED:
Due to the fact that the rectangular head on the Sensepil is roughly twice the size as the round one on the Tria, the Silk’n covers more area faster than the Tria. Expect the Tria to take almost twice as long to complete a session – and a little longer still if you need to re-charge the battery halfway through.
EASE OF USE:
The trade-off for having to re-charge the battery with the Tria is the ease of use that comes from it being a cordless device. Beyond that, with the Sensepil there is always a concern that your cartridge will burn out halfway through a session – especially if you have not purchased a replacement.
EFFECTIVENESS:
The December 2009 issue of Good Housekeeping reported that, “Published studies showed that the Tria reduced overall hair re-growth an average of 41%, and the Silk’n by 43%, six months after a series of 3 treatments.” Although this published study states a slightly lower figure for the Tria in overall hair reduction, it also states that in this same time period, the Tria reduced leg hair re-growth by 61%, versus 54% for the Sensepil.
Find the best price on the Tria at Amazon.com