I myself was waiting for the Taycan, its looks stunning, and is very impressive, but on pure specs, its actually the same size as a Model 3 Performance, and a little slower... So I just ordered a Model 3 Performance. I currently drive a Model S.
Honestly, the Model 3 and the Taycan will probably be miles apart. Some of my own reasons for wanting to wait for the Porsche instead of getting a Tesla:
Handling: There is no way the Tesla will handle similarly to a Porsche. Steering feel, cornering, road feel. Porsche is the king of handling for a reason, and I'm anxious to see what they can accomplish with the low CG of an electric vehicle.
Consistency: The Porsche can keep doing pulls from 100% down to 10% charge consistently with no performance degradation. This was actually Porsche's main focus, an actual electric track car.
Fit and Finish: Again, anybody who's seen both a Porsche and a Tesla up close will know it's not even a competition.
Charge Time: The Porsche will charge twice as fast as a Tesla, which (assuming you can find a fast enough charger) is pretty cool for quick recharges.
You don't buy a Porsche for 0 to 100 performance as there are better cars on the market for that. You buy a Porsche because you want the fastest track cars that will best any other car on the Nurburgring. The Taycan will be the fastest production electric car on the Ring.
I think there is a very high chance, that it will be, but right now the M3P, is beating even the BMW M3 and Mercedes C63 AMG around tracks, as shown by Top Gear and others. I do however think that people buy them, because they are performance luxury cars, with a great interior, and great features. Thats why I was looking at it anyway. Unfortunately because of the danish tax system, and when the car will be available, the Model 3 Performance, makes much better sense for me..
Porsche occupies a very interesting part of the market. At the low end it competes with BMW/Mercedes.
At the top end (Turbo S/GT3/GT2) it starts to compete with Aston Martin, then McLaren, then Ferrari/Lamborghini/etc. You can spend £45k for a basic Cayman up to £180k+ for a heavily optioned 911 Turbo S and more for lower volume/limited editions like the GT3, GT2 etc. (ignoring eg the 918)
So where the Taycan as a range places within that is quite relevant. All the signs at the moment are that it will price similar to the 911 ie probably starting at £65-70kish. But we only have one data point which is the £130k for the Turbo trim level.
The all-wheel drive dual motor car it's going to be around 130k USD. With that amount of money you could easily buy now any Model 3 (which could cover the day-to-day) AND another internal combustion engine car. I mean: okay, you'll have to maintain two cars vs. one but still.