They may be the same or slightly different. For Example, a Jet 1014 VSI is considered (or at least marketed as) a "mini lathe". It has 10" Swing over bed, 14 inche turning length (without bed extension) and a 1/2 HP motor.
The new Delta has (I believe) a 12" swing over bed, a little longer length without extension and a 1 HP motor. The Delta is marketed as a midi lathe.
In most other areas, such as MT2, head threads, etc. these two lathes are very similar. SO.....This means you should read ALL of the specs for ALL features of each lathe before choosing.