I haven't cycled there, but I have been there, and the whole time I was wishing I had my road bike with me! I also saw lots of cyclists on the road in full kit (often touring), so it's a popular place to cycle - For good reason, there's some lovely cycling area out in the country and along the coast.
The quality of driving seemed to be reasonable (completely unlike Bulgaria, where it seems like everyone is trying to run you off the road!) although as I said I haven't cycled it.
One thing to note is that whilst the main tracks and roads are well surfaced, a vast majority (at least in the area I was in) of minor roads are dirt or gravel, so tough tires are a must.
And obviously it's extremely hot in the summer, but I guess you'd be used to cycling in the heat from your TransAm tour!