harloo. user of AL vs4121, mx5021 and Edifier m3400, m3300 here ^^
here are my comments...
Altec Lansing Vs4121...hmm...this speaker, as many ppl say it sounds imbalanced. I bought it long time ago cuz it was one of the speakers that stand out BACK THEN. vs4121's bass is loose. loose means..lik the bass u hear in cinema. NOT heart-thumping every note(tight). Takan every bass note in the movie u wan your body to feel meh like in a concert...by the time exit cinema whole body numb numb edy
The woofer doesnt go as low as it claims (25hz). By the time 38hz it struggles and reaches its extension limit easily. The mid range is down firing(facing the table) so its subjective to the surface your table is...if glass it would sound harsh, if high quality wood it would sound warm, if low quality wood the midrange would sound very "tin-can"ish. Tweeters...well ntg much to say...it doesnt go that high lah. The major letdown of this speakers is the bass to midrange...not smooth at all. When soft the woofer is dominating the sound and when blasted loud the satellites distort leave the woofer behind by miles. The sound quality will really depend on the room enviroment too and will change on your listening position.
Altec Lansing Mx5021...hehe. Can smile edy

not too much

mx5021 well its THX certified so it generally sounds good but to me it could hav been better. The "presence" of the treble can get annoying. esp if u listen alot of rock,metal with alot of electric guitar or techno/rave music with alot of electronic sounds and ambient. If u're 3 or more meter frm the satellite its ok but if ure nearer it can get annoying after prolonged listening. For pop, rnb, rap the bass is very very well mannered but for techno the bass isnt tight enough for the oomph. However its perfect for movies. Placement of speaker and room enviroment is not so important cuz i think we can agree that all mx5021, if we stand 3 meters or more they tipically sound the same throughout the room. i think thts y it got THX certified
well...to me thts how they sound...just my 2 cents loh.