T10 steel is also known as tool steel. It is the most common steel available on the market and thus, less expensive.
Don't mistake this for less in quality. T10 tool steel has the most similarities with tamahagane than any other steel available on the market.
The base of the T10 steel is carbon and iron. The carbon contents is between 1.0 and 1.1% with some small performance enhancing additions. However, this is less than 1095 steel so you can say the steel is a bit purer.
Polishing T10 steel in kesho hadori requires really specific stones due to the hard surface. However, since 2012, Kaneie Sword Art has the capability to also perform a kesho hadori polish on T10 steel blades. The positive side to traditionally polishing T10 steel is that nugui reacts much better due to the simplicity of the alloy.
1095 steel and T10 are so similar that it is nearly impossible to identify them without metallurgic research equipment.