Electric pianos have a number of significant advantages over their more traditional acoustic cousins in that they are smaller, portable, stay in tune and have headphone sockets. The disadvantages can be the lack of `real pedals, the sound quality and the feel of the keyboard.
The `P' in P70 stands for professional and that is a clue that this is a serious piece of kit and not a toy. Sure you can get cheaper keyboards with more features, but where you should ask yourself have the compromises been made.
If like me you're still learning then the weight and feel of the keys is perhaps the most important aspect. The P70 has Yamaha's Graded Hammer Standard Keyboard (GHS) with beautifully weighted, touch sensitive keys and feels very similar to a real piano, making the transition from one to the other easier. I found it tough going to a lesson and using my teachers heavy acoustic piano when I'd practices on one with an over light touch. This was the primary reason for getting a P70.
The Piano sound is really very good indeed and makes this an ideal piano for performances. It's easy to carry too; I regularly take mine with me when I'm staying away on business trips and use my headphones. I would have no hesitation in recommending this piano but for one thing, the Yamaha P85 is now out, is better specified, is slightly smaller and at a similar price.