AD3 is better than AD2: 1. If one channel of the oscilloscope is not used, then its buffer can be given to another channel. Those. The maximum buffer length with one channel is 64K. This is cool. 2. Digital I/O in AD2 are always pulled to ground. In AD3, the pull-up can be either to ground or to power, or completely disabled. This point is quite important for me. For example, for working with I2C chips. 3. In AD3, you can select a clock frequency other than 100 MHz. Sometimes this can come in handy too. Well, that's it. AD3 is worse than AD2: 1. AD3 cannot work with 1.8 volt circuits. My conclusion: if electronics is your hobby, you have a little extra money and you don't have any ADx, then it's better to get an AD3 for the future. P.S. At the last sale with all the discounts and coupons, the AD3 was $250 plus shipping. I bought a bundle with probes and a carrying case for $300. This is comparable to the price of AD2.