As I said I am not definite about the bass/overall audio quality yet and the bass can be really week then others because of following reasons.
I used Z506 and it gave me better bass because it has 30W subwoofer where as R401 has 24W. Z506 also have week mid-rangers i-e 8W where as R401 has 12W mid-rangers, Z506 also lack tweeters while R401 has them so its natural that bass is dominant in Z506 and R401 producing more balanced sound. Apart from these technical reasons I used Z506 in different room (smaller and packed) and yesterday I used R401 in larger and open room (with generator and couple of guests noises) so it natural that I feel low bass (placing of woofer to ideal place matter alot). Tonight I will place them in same room and will play same tracks which I used to play mostly on Z506 then let you know.
On other end I am a little audiophile whihc you arent
so what ever you get seriously you wont feel much difference (considering its your first purchase)
One important thing I would like to share that with Z506 I always have issue watching movies on it, due to week mid-rangers it was really hard catching dialogues (vocals) in lot of scenes. That's one of the primary reason why I dumped Z506.