Before we got the CS we had an elektra beckum kgt500 and the elu flipsaw. They were both (ab)used for a long time to the point that accuracy was a thing of the past, and neither had any form of dust collection. I hadn't heard of the brand mafell till after we got the festool plunge saw and the CS. Here is a link that sums up the accesories for the erika when you scroll down:
link (It's a pitty they don't have pictures for most of the accesories) I like the add-on routertable. (festool is introducing a similar one for the mft3, which will probably hook up to the cs aswell, but I believe that one needs supportlegs)
I have never seen their erica saw in person, but I did see their chain-mortiser and a demonstration of their jobsite panelsaw (like a ts 55, but it does the cutting by itself) at a fair.
I did read a positive review of it at a German forum, but I can't find it anymore, I did remember that that person liked the upfront controls, but when you lock the CS's blade in the front position the bevel and height controls are also upfront (allthough slightly less easy to reach than on the mafell from the looks of it).
Just by looking at the pictures, the advantages of the festool over the mafell seem to me: the splinter guard, the easier blade change (from above the table, due to the removable inlay), the lower price and the groove for using a festool rail clamp as a holddown clamp.
The system bonus for me is that the extensionwings of the kapex set fit the cs 70 aswell. Haven't them with the cs yet, but I will next time I have to cut aluminum profiles.
I did have a problem with my CS recently: when cutting thin strips I noticed the fences aren't 100% parallel to the blade anymore (in the vertical plane, they are still parallel and square in the horizontal plane, and the blade is still perpendicular to the table) I still have to contact festool about that to see if they can fix it and how much it would cost me, I was going to do that at a building fair last month, but I couldn't find the time to go there.
The missallignment is probably caused by the saw being banged around in my van and maybe because I replaced a worn rubber foot too late.