I recommend Egeria najas over egeria densa ('regular' anacharis). In my experience, the Najas has been more resilient, grows just as fast, and (purely opinion on this one) looks better due to its density of small leaves once it gets going.
The najas variety also takes Excel consistently without flinching, while the densa may tolerate it for a bit but tends to melt eventually. I've also noticed that while many of my fish (catfish, killies, cichlids, barbs) will eat/try to eat the densa, they never touch the najas.
Just something to consider. Both are still great low maintenance plants regardless.