How practical is a Tri specific bike?

This winter (2010) I decided that I wanted a more road biased bike for competing on.  My biggest concern was that my training is my commute to work, so I was concerned that a triathlon specific bike may be unsuitable for commuting.  I checked a few websites, but the standard view was that I should go for a road bike.

I decided that I'd go for it, and build a tri specific bike.  I based it around the Planet X Stealth Pro Carbon frame-set.

Is it any good for commuting? - Although it took a few rides to get used to something other than a XC bike, the bike works well for commuting.  I carry my work clothes, shower gear, bike repair kit and a heavy duty lock in my rucksack - and I've really enjoyed the experience.

So if like me you want a bike for Triathlons, but will use it as a daily ride - you should still consider a tri specific bike.

Are there any downsides? - these are below, but nothing that can't be dealt with:

• Brakes... compared to the hydraulic disc brakes that I'm used to, road bike brakes aren't that good. This isn't a tri-bike issue, but it feels wrong that I can be doing 40mph, and then struggle to stop when the lights change.
• Lights... I haven't yet found lights that will fit on the bike, due to the shape of the frame.  However, there is a guy at work who has some very tiny lights... I don't know what they are yet, but they look like a good option.
• Finally, I haven't got over the new bike thing yet - so I'm very cautious about where I leave it.  At work I have access to the secure-ish car park... I haven't risked leaving it at the pool yet!