I too own CycloDS and Acekard 2i.
I bought Acekard because it was so damn cheap and I was PLANNING to get DSi (a plan that was not executed completely)
I find myself using more of Acekard 2i - mostly just because it loads about a second faster and has more smoother UI (MAY BE CHANGED IN FUTURE, yet to see what kind of sexy stuff team cyclops is to offer in possible update in near future)
For games: Both are in same line
In features: cyclo wins with RealTimeSave (Slowdown is useless feature) - OH, there IS ingame text reader. I just remembered it, that was how much I used it ever...
Acekard wins at moment with speed (initial boot is side-by-side tested by me with two flashmed (no health warning) DS lites, and cyclo boots to menu a second later than acekard. Plus acekard is more intuitive to control by touch (cyclo at moment (may change in near future) is kinda clunky, and my biggest debacle is with it misregistering touches and slides, ending up booting games when I just wanted slide the cursor down)
So... My bottomnline in recommendation is... Acekard 2i at moment (2i because of hardware problems in 2.1, it does work on all models) - Cyclo Has features but game compatibility is same, and updated really fast as well. (On both) - bottomline is; Is real time save and ingame text reader worth 30bucks extra?