I have used the following:
PolarFlo TT
Stinger V6
Stinger V8
I like these because they are not widely used which gives them an "elite" sort of "aura". They are also some of the top performers out there. The Stinger blocks are custom made.
1. im been checking the stinger out, any company that doesnt have the internals clearly displayed on a block worries me.
http://www.stingerwaterblocks.mysite.com/2_column_page.html
im sure thats the manufacturers homepage. And the funny thing is the owner seems to be bragging about these score
Stinger V-6...WC ..3019-MHZ..http://valid.x86-secret.com/show_oc?id=170538
CPU-Z ValiDated..3044-MHZ...http://valid.x86-secret.com/show_oc?id=170545
CPU-Z Validated...301-FSB....http://valid.x86-secret.com/show_oc?id=170127
CPU-Z Validated
ummmm.... LOL my d-tek fusion allowed me to push my AMD @ 3080 MHZ, so overclock has no bias in my book. Infact, the WR on the QX6700 was currently scored by Fugger on a ApogeeGT. I Posted my proof on a earily post.
Also im having the hardest time finding them on sale. They seem to be almost as rare as cathars G4. <--- THE BEST BLOCK dont argue with me. There are only 3 blocks i can think of that are made of entire silver. 1. is Cathars G4 <--- the sucessor to the storm rev.2 also a uber expensive block, USED would run you near 300 US dollars.
2. danger den TDX silver edition. Also extremely rare, havent seen ANY on sale yet.
3. I hear swiftech will come out with a uber version of there apogee in silver. This is still a rumor. Expect prices to be near the 200 range for this as well.
So, i would honestly pick a block which has been shown by Thousands, and not a few select group to perform well. That would be a D-tek Fusion, or ApogeeGT.
Also op, having a block which most people own, makes things easier for you when something goes foul in your loop. Im sure someone will have repeated the error your getting, and its far easier to help with a block were acustom to instead of a rare and super bling bling block.
BTW, not to laugh at you or anything, but POLARFLO!?!?!??! comon, that block was shown to be a serious POS. You need to use its 1 inlet and 2 outlets to get its cooling somewhere decient, and even then, an RDX wiould pwn that block.
ummm incase your wondering, the currently block hierarchy to my knowledge would be this as follows:
TDX > RDX > Apogee > Storm Rev.2 > ApogeeGT ~ D-tek Fusion >~ ApogeeGTX
> <--- is less then
~ about the same maybe tad bit better
Im taking a guess on the ApogeeGTX. This is because its suposed to perform better then there apogeeGT. ApogeeGT with Oring modifications have clearly shown to perform as THE KING. IF you want more info, google, swiftech's CES challange. You should get a challange swiftech hosted. Swiftech Won that challange with there apogeeGT thanks to the infamous O-ring mod.