What do you think of the DIY Cat 5 speaker cables

clarification. I just read about weaving your own.

no way,

my method is to use Cat 5 out of the box, which is jacketed, within: 8 individualy insulated small diameter solid strands. Twist a pair of them, gives 8 wires positive, 8 wires com.

Everything individually insulated, everything internally twisted.

Strip the 8 wires, pressure them into 1 squished copper mass ready for a gold plated connectors, DONE. In no way difficult.

Badcap - I have not tried CAT5 for speaker cables, but I have tried it for interconnects. The results were OK, but far from stunning.

From a design perspective the cables you mention would be of a higher capacitance, which is something to consider if you are using them with a Solid State high current design amp. The amp could experience oscillation, which could seriously damage the amp.

If you are into DIY, take a look at the following...
http://image99.net/blog/files/category-002ahelix-speaker-cable.html

The helix cables are the best I have built to date. They outperform most of the commercial cables I have auditioned, some of which were quite expensive. 

You can use any wire you like, but the wire identified on the site has been tried recommended by myself and other DIYer's and offer the best performance to date.

Don't be put off by the looks - they are pretty easy to build and even though the coiled neutral might lead some to believe their Inductance would be an issue, I have measured it at 1.1uH/meter, which is well within acceptable levels. Their capacitance is in the low-medium range at 60 pF/meter.

Unfortunately, construction of the coiled neutral for most DIYer's can get tricky if you want cables over 12 ft long.

I have had feedback from others that have tried them and it has all been extremely positive. The cables seem to work very well on both tube and solid state.

They provide stunning dynamics and clarity, with a well controlled and deep bass and a very spacious and detailed image

If you have any questions, just ask - Steve

I have done it myself but I think the cable may have a bit too much capacitance.  The sound lacks a bit of transparency and the bass is a bit compromised.  And those CAT5 cables are not cheap.  I think you're better off buying some decent affordable speaker cables such as QED or the likes which have quite better transparency.  

If you want to do DIY jumpers and/or speaker cable, see if you can google the Stan Warren recipe using THHN wire.

I think Reality Cables uses basically that formula (I could be wrong) but they offer higher quality wire than regular Home Depot THHN and they cryo treat.