Benefits are: it's a break-beam eye instead of sensi/cops - which _should_ be a more reliable and foolproof anti-chop system if setup correctly.
The board gives you the ability to use the eyes, no board, no break-beam. You'll also use standard 9v batteries rather than the normal Angel battery.
Dunno the cost but in the states a similar setup (either WAS or TheAngelGuy's Predator) would both set you back $350.
Downsides are: If sensi/cops isn't causing you any problems then it's a waste of money.
Most of the setups I've seen use boards without LCDs, so you'll be losing all of your IR3 bells n whistles.
On the bling side, most of the mods have the eyes epoxied onto the bodies and look cack - TAG's Predator will come with eye covers, so should look a bit tastier.