Many accountants recommend against the status of AE, for a number of reasons, but it all depedns what suits your own particular circumstances.
Setting up and/or modifying an SARL can be quite costly (just to take over an existing one cost me around €1200), and the HUGE inconvenience is that ALL of the partners will have to contribute to the RSI (that's the NI service for self-employed people) — which is currently coming in fro a lot of flak and is to some extent in turmoil; they are notorious for their inefficiency, mistakes, and strong-arm tactics when it comes to recovering their money.
As a rough guide, the RSI contributions will be around 48% of your PROFIT; of course, you can arrange your accounts so you don't make any profit, BUT there is still a minimum contribution of something like €1800. I don't quite know how they calculate it, but it seems this minimum contribution applies to EACH partner; so if you start an SARL as say a husband and wife team, even if in your first year you don't make any profit at all (on paper or even in reality), you will still have to fork out a fairly hefty sum to the RSI.
So depending on the nature of your business as well as its scale, you might find AE is a good way to start up. I was originally a micro-entreprise, and I was struggling to find €600 a month to pay the RSI, given that my freelance income is highly variable from month to month. When I changed over to AE, not only did my overll charges drop slightly, but also, I only had to pay a percentage in any month I had actually earned something — and I had a month to pay it in. To me, that was a life-saver.
There are many changes affot, it is high time the whole system was reformed, so make sure you do have the most up to date information!