The Aer Lingus business class cabin is fitted with angled lie flat seats from Recaro which are very similar to what a number of other airlines feature, there's also only 24 seats which make it quite a cosy cabin experience.
There's more information on the seats here:
Business Class catering:
The economy product isn't bad either, cabins are comfortable and there's the usual AVOD entertainment system you'd expect these days but the economy meals never look too appealing and theres a charge for alcohol which is probably why they've started offering an online meal upgrade service.
I'd definitely go for business class if you were really considering it, the product may not have all the bells and whistles that the premium carriers have but it's still a very nice way to cross the Atlantic.