I have BOTH of these cards, so I can comment on this reasonably well...
First, you should know that both of these cards share the SAME reference board design and reference driver package. They carry the same engine, and differ mainly in driver quality and, to a certain degree, features.
I started with the Hercules Game Theatre XP (GTXP).
I purchased it when I had enough of the problems with the hardware and software of the SoundBlaster Live Cards. A man can only take so much
I loved the GTXP from the moment the box came in the mail. Talk about HEAVY!
At the time, Windows 98 and 2000 were the predominate operating systems, with XP just a dream at that time.
It worked beautifully under Windows 2000 and 98. There was an issue with people running systems with more than 512MB of RAM, and this was a driver issue. This did not affect me at the time.
I praised the card daily on the newsgroups I visited. I still do, really.
However, then the Windows XP Preview came out, and it went downhill from there.
For reasons I don't understand, Hercules, for the longest time, would not comment on Windows XP compatibility. To compound the worry, several store chains, such as Best Buy, pulled the GTXP off of their product list.
It did NOT look good for the GTXP.
Finally, Hercules said something. I guess they needed to stop the ship from sinking But, it wasn't really good news. There would be NO drivers until November of 2001 (this was mid-summer of 2001, I believe, when this came out). However, Hercules was refusing to provide any basic beta drivers for folks to use and to tide them over until November.
That was it. The GTXP was holding me back from WinXP, and I had to make a change.
There was no way in hell I was ever buying another SB Live card, so I looked at the Turtle Beach Santa Cruz, and I decided to purchase one. I chose it because:
1. It used the same basic engine, reference board and reference drivers as the GTXP.
2. The reviews were generally excellent.
3. It has been noted as a particularly trouble-free card.
4. There were beta XP drivers available that were noted as working perfectly.
So I bought one.
It was 1/2 the price of the GTXP ($79 at the time, cheaper now I think).
This was in, oh, September of 2001.
It has been in my computer every since, and has never, ever failed me in any way.
Turtle Beach has been excellent in keeping the drivers updated, and each revision has improved the card slightly. Most releases were to fix esoteric issues that most people didn't have anyway. Very solid drivers!
I still have the GTXP. It's in the box, and will get used in a computer again, some day, now that Hercules released XP drivers (and did so in November 2001).
But, I have no motivation to change it back in. The TBSC has worked perfectly, has caused ZERO issues, and has, for the first time, been a sound card I just plugged in and it worked. No nannying required.
To add to that, the TBSC has 95% of the features the GTXP does at half the price. The main difference is that the connections are made on the back of the card instead of the Hercules Breakout box.
There are a couple of things missing...
1. The USB Ports. Since the GTXP USB Ports are unpowered, I had problems with them anyway. No loss here.
2. The GTXP has RCA connectors instead of mini-plugs. Doesn't bother me, really.
3. Additional Headphone/Microphone controls on the Breakout box. I don't use a Mic, and I have a Headphone Jack easily reachable on the control-pod of my Klipsch ProMedia 5.1's.
4. The Digital Inputs/Outputs on the GTXP are more flexible, but the "VersaJack" on the TBSC takes care of anything I need.
None of this really makes me want to/need to pull the TBSC and put the GTXP back in.
The TBSC has a few merits of it's own:
1. The driver solution is EXCELLENT. Stable, and trouble free under Win2K and XP. Never had an issue with >512MB systems.
2. In a way, it's more convenient (based on the way _I_ use a sound card) to have the connectors on the back of the card instead of having a break-out box on the desk.
3. Did I mention the excellent drivers?
4. It has digital connectors on the board, internally. The GTXP does not have these. To me, this is more usefull than the digital I/O on the GTXP's breakout box.
So, if you ask ME which one to buy, I'd vote for the Turtle Beach Santa Cruz unless there is something very specific about the GTXP's breakout box that you really need. Don't purchase based on the USB ports. Get a powered hub instead if that's a need.
One thing has always confused me. Turtle Beach had no problems providing beta drivers for XP, and in fact had FINAL WHQL certified drivers out for WinXP a month and a half before XP final even shipped.
Hercules not only would not provide beta drivers to tide folks over, but didn't have final drivers available until after XP shipped.
What confuses is me that both of these cards share the same basic reference hardware and reference driver set. What did TB know that Hercules didn't?
Well, that's about it. The TBSC can save you a lot of money over the GTXP if there isn't something specific to the GTXP that you simply must have.
Hope this helps!