Asus G551 does not come with subwoofer. Price wise, Asus G551 is cheaper than Acer V Nitro by ~50 bucks if i remember correctly after nego. I ended up with Acer V Nitro due to following reason:
PROs:
1) High spec does not require upgrades (for most user if not all)
2) Mainstream look compared to gaming look although not overdone on the Asus G551 (using for work and entertainment @ home/on the go)
3) Elegant soft touch/rubber (as premium as aluminium)
4) Dual fan gooding... can feel all the heat coming out after intense gaming D3 & BF4 highest setting. Does not feel uncomfortable to me...
5) Low fan noise!!! indeed..
6) The IPS screen is definitely better than TN panel! But comparing with other high end IPS screen? Idk, but the budget for such quality is already considered jackpot.
CONs:
1) Maintenance cover is pain-in-the-arse for normal user (do not even think of opening it before warranty expires)
2) Any upgrade to be done including HDD>SSD is to be done at Acer SC to prevent warranty void & clarified by Acer SC if laptop to be send in for warranty claim, need to change back stock hardware.
3) 4 speakers all at the bottom of the laptop, sound is not natural if you place directly on the table as the sound get reflected but place a laptop cooler below and its quite alright (sound quality not as good compared to my colleague's Asus G56 w/subwoofer)
4) Other review says the V Nitro keyboard is better than the Y50.... with this I can conclude Acer and Lenovo's keyboard are bad! (to me only) The Asus keyboard is only slightly better. Anytime will prefer the more standard laptop keyboard.
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My advise to fellow forumer hunting for either Y50/V Nitro/G551:
Lenovo Y50 - Take this if you don't mind the TN panel screen quality. Sound quality is good with built-in subwoofer, well-spec, beaufitul design and slim design. Was the king of affordability until the 2 came out of nowhere... dang..
Acer V Nitro - Price do the talking and without considering any upgrade compared to the competitor, this is the ONE! DIY maintenance on the laptop will be tricky but give it as a chance to know your laptop inside out

oh.. this baby is slim too!
Asus G551 - Bulkier design but as for gamers, we believe it provides better airflow compared to compact design. Choose this at all cost if you are looking for gaming look! Do not let others tell you off to own a ROG badged laptop you have always wanted to

... now at a more affordable price. Regarding the subwoofer.. you wouldn't use it on the go anyway so not providing one does not take the ROG DNA away.
Conclusion: All these 3 laptops made the pricier gaming laptop seems even more expansive..... My comment on buy these or wait for GTX900 series,
buy when you need it is the priority. You will never be able to catch up with newer technology (new model every 3-6months).