I am in a very simlar situation, between the YAS-71 and Sony HT-CT500. Some more data points of note:
1. warranty: Yamaha is 2year labor+parts, while Sony is 1 year labor+parts
2. Features vs. price: Sony has more features, including HDMI, upscaling, component input etc., while Yamaha has only the minimal features that are really needed. I am somehow tempted to think that hence Yamaha provides high quality for provided features, but Sony may not, since there are a lot of features, both for given MSRP (Sony = 500, Yamaha = 600), I dont know if this is a valid point to compare, but please I just mentioned it for whatever it is worth.
3. Speaker frequency response and THD specs:
I could not find the frequency response for the Sony speakers. An interesting point to note would be when the sub crosses over and the overall frequency response range. It looks like the YAS-71 is 35-120Hz (Sub) and 120Hz-20Khz (other speakers).
• Type 2 way acoustic suspension magnetic shielding type
Woofer. 8 cm (3") cone magnetic shielding type x 4 (L2, R2)
Tweeter. 2.5 cm (I") balanced dome magnetic shielding type
• Frequency Response 120 Hz to 20 kHz (-10 dB)
• Dimensions (W x H x D) 800 x 105 x 100 mm
(Approx. 31-1/2" x 4-118" x 3-15/16")
• Weight 5 kg
(Approx. II Ibs.)
• Minimum RMS output power per channel
LlR 55 W + 55 W (I kHz 1% THD + N)
Subwoofer 55 W (100 Hz 1% THD + N)
• Maximum power per channel
LIR 70 W + 70 W (I kHz 10% THD + N)
Subwoofer 70 W (100 Hz 10% THD + N)
RMS output power FL/FRlC*: 100 watts (per channel at 4 ohms, I kHz, 10%THD)
Subwoofer: 100 watts (4 ohms, 100 Hz, 10% THD)
4. LPCM: Sony supports LPCM, hence the Dolby True HD, DTS-HD codecs, if uncompressed to LPCM by the player and sent to this unit, can be played. But, there is a limitation (quote from crutchfiled web site), I do not know what this means:
Note: This system does not support Dolby Digital Plus, Dolby True HD, DTS-HD or Linear PCM sampling frequencies of no more than 48 kHz
However, anyways we are going with soundbar foregoing true 5.1 or 7.1, hence I do not know if it will matter between Dolby Digital vs. Dolby True HD.
Overall, I am inclined to go with the YAS-71 vs Sony.
Denon DHT-FS3, MSRP $1200, available in Amazon for ~$400 is another choice I am looking at. CNet review of that says it has a "wide surround field" available only in the higher priced Yamaha YSP models; this point is attractive to me.