The Picosure and the Enlighten are both picosecond lasers and are actually concurrent technologies. The price per treatment is always going to be relatively the same, the difference mostly lies on the end of whoever is purchasing the laser, not the recipients of the beam. Which is better is mostly dependent on what colors your tattoos are, as they can run at different wavelengths which can be more or less effective depending on the color of ink used.

If you're looking for an alternative you would want to look into removal using a nanosecond laser, which IS older technology. Unfortunately, these lasers are less effective and require more sessions to remove the same tattoo. This means more pain and in the end you end paying about the same amount of money, it's just spread over more treatments.

If you're just looking to lighten in order to cover an old tattoo with a new one, a nanosecond laser could be a viable alternative. If you're looking to completely remove a tattoo a nanosecond laser is cheaper per application, but those sessions add up and I'd recommend just continuing to use either the Picosure or the Enlighten (the only two commercially available picosecond lasers on the market).