I need a new bike. All I have is a 14yo mountain bike and I really feel like I’m fighting the road with it. I’ve got a number of good bike shops near me that cover the major brands very well. The one I like is big on Specialized. I test rode a Roubaix out there yesterday and wanted to try an Allez, but they didn’t have one in my size. I really enjoyed the Roubaix and it just went on sale. Any feedback on that model or what I should be looking for?
First, you need a road bike if you want to do a tri of any substantial distance (if you have never done one sign up for a sprint and use your mountain bike.) At some point you are going to consider whether you also need an aero bike. I don't recommend that until you are seriously participating in tris on a regular basis.
As to the road bike, I have no advice on specific brand. The various shops are going to push the brands they are licensed to sell. Road bike frames are fairly similar from brand to brand - and most probably get frames from the same manufacturer in China. I would say that you should focus on the following:
1. Type of frame (carbon, aluminum, steel etc). Carbon is likely your best bet and most stock road bikes are going to be carbon. If you are looking at a lower price point aluminum will be fine.
2. Components. This is the most important consideration and the factor that will drive the cost. Lower price point bikes usually come with cheap components. They will wear out quickly. Take some time to learn the various component levels. For example, if Shimano components I would not go any lower than Ultegra level.
3. Wheel set. For now, go with the stock wheel set. You can always purchase a better set later.
4. Price point. This is really a compilation of items 1-3. I would not compromise on the components. Also, the best deals are usually found on Craig's List, ebay etc. I purchased my Felt road bike from a dealer but luckily found my size in a year-old model right when the new models were coming in. I found my Scott aerobike on Craig's List. $4,000 value for $1,000. The seller owned it for less than one year, rode it less than 50 miles and sold because the Air Force was transferring him. The race wheels cost more than what I paid for the bike.
Whatever you purchase, make sure that it is properly fitted. Good luck.