[Spark]

Smaller lathes are cheaper, however smaller sizes can be killers on precision. If your doing non-critical shapes then small lathes are good but if you want precision definitely go for a bigger lathe. It really matters what you're going to use it for. Sometimes its better to spend a little more money and get what you need.
Also be careful using carbide, its great but it can chip too. The smoother motions you can do the less chance you risk of damaging your cutter. Its the same way for mills, unless you use CNC machines its actually recommended you don't use carbide.