Xonar U3 is not the blind choice to get in this battle.
The Xonar generally sounds a little better for music, but that's where the buck stops.
The X-Fi Go Pro! (not the 5.1 version) may be the bigger brother of the XFi Go Pro, but it is inferior in one very crucial aspect: lack of CMSS 3D Headphone support. For some reason, the vanilla Pro has this option whereas the 5.1 doesn't. From what I can tell, Creative intends the Go Pro to be a laptop card for use with headphones, whereas the Pro 5.1 is designed to be used with a desktop connected to a larger soundsystem that doesn't need headphone support. And looking at the feature set of the two, the Go Pro seems to be designed with games in mind specifically.
This is very crucial because, depending on how you intend to use the soundcard, the U3 is vastly inferior to the Pro (not the Pro 5.1) in some ways, the key one being games. For gaming, this has been beaten to death but some people swear by Dolby Headphone and some by CMSS Headphone for positional audio in 3D games. I guess it depends on the HRTF of your head, but CMSS Headphone is by far much, much better for me than Dolby Headphone when it comes to rendering the sounds in a positional 3D landscape around my head. I can tell where the sound is coming from precisely with CMSS headphone, with Dolby it seems like just a flat 2D plan to the left and right.
The same effect occurs with movies with good surround -- CMSS is better for me than Dolby.
As for the Pro 5.1, I find it sounds better compared to the U3 when all options are off.
So the answer here is not so simple.
1. I will use this for music. -- Get the Xonar U3
2. I will use this for gaming on my laptop, use a headphone, and my head's HRTF works for CMSS HP - get the Pro
3. I will use this for movies on headphones - depending on HRTF, either U3 or CMSS
4. I will use this as a pass through to my digital home sound setup - get the Pro 5.1
5. I want to use the Dolby stuff with my home setup - get the U3
The Xonar U3. Hands down. I have both the the Xonar U3 and the X-Fi 5.1 Pro USB (bigger brother of the X-Fi Go).
Both sound good on all effects switched off and no custom equalizers. But the surround sound options are where they are worlds apart.
Xonar U3 has Dolby Headphone, Dolby Pro-Logic IIx, GX2.5 EAX emulation and Virtual 7.1 speaker shifter amongst other features. It can also output Dolby Digital Live in real time via TOSlink optical out,
The X-Fi has only THX surround, no Dolby features what so ever. Its the trend now with creative products as they have abandoned the CMSS-3D features of their own versions of the HRTF implementations. And honestly they sound like utter trash. CMSS-3D sounded better but this is THX, totally different and vastly inferior
Get the Xonar U3 and you will be able to choose DH1 DH2 and DH3 modes of Dolby Headphone surround modes in 2,4,6 and 8 channels. You can set 7.1 channels in windows or via the Xonar control center and then choose output as Headphone and enjoy great surround sound.
If you are not in it for the surround sound, even then the Xonar U3 is a better buy because its drivers are free from the bloatware creative bundles with its products. Besides am comparing this to the more powerful Creative USB solution, the X-Fi Go is generally regarded as very poor compared to the one I have.
The Xonar U3 is compact, feature rich and really performs better than the bigger USB class sound cards out there.
As along as your headphones are not more than 80-100ohms the exciter mode on the Amp that is built into the Xonar U3 should give you lots of drive power. I don't even go beyond 3 taps on my sound panel and its already loud for my 32ohm headsets and that was barely 2% volume level on the highest exciter mode. But to really enjoy any decent sound card a good pair of headsets are needed. Depending on your budget the guys here can make good recommendations. I just ordered a HD 598 to go with my Xonar U3 as I crave for a wider airy sound stage.
As for my rig, I have a M18X-R1 laptop and the on-board was as expected too weak for surround sound options so I looked to get a decent sound card that could output Dolby Digital Live to my Stereo headset's decoder for virtual 5.1 Dolby Head phone surround. I first got the Creative X-Fi 5.1 Pro. But there were way too many cables and clutter on my desk with this setup and I have no control over the Dolby headphone mode like DH1 or DH2 or DH3. Then I did my home work for real and understood that all I needed was the Xonar U3 and connect my Headset directly to it and I can get rid of all the wired mess of the control box. So simple. Laptop to Xonar U3 straight to the headset/headphone. No clutter and works great in Dolby headphone mode and the best part being I can customize the modes and other effects.
I even posted my short review on newegg.com, so to avoid copying it all over again I shall just link it here. The 2nd one from the bottom by the Name of Viki.
Hope it helps.
Edited by Mochan - 4/13/13 at 12:14pm