First of all, I'd strongly recommend starting on Tech 4 for your first games (or all games TBH). Tech 3 is very 'gamey' at the moment.
I respectfully disagree with this conclusion, and actively encourage new players to play Tech III.
Tech III is an additional layer of difficulty in comparison to Tech IV start for sure, but it teaches you things you cannot learn on tech IV starts.
Tech III teaches you to focus on discovering and researching the right things, like how to fight energy shortage, prospecting for resources, or modelling a tank unit that has a high early game survivability.
Tech IV gives you energy tech from the start, and you are not bottlenecked into getting some sort of energy production discovered, making you miss out on the tech research mechanics that will help you in later games discovering and researching those tech you want vs those techs you want later.
Tech IV gives you a rare metal and metal deposit right from the start, and you are not forced to prospect or build recyclers early game to get those resources, missing out that struggle experience that helps you in later games or games with different resource shortages.
Tech IV gives you a free light tank model, which is really poorly designed at least.
Without the model design discovery-chain experience, you will miss out quite an interesting game mechanic. With that I mean you do not want to model artillery, bikes or APC until you discovered light tanks because this will widen the range of discoverable models, making it more difficult to discover light tanks at all.
And if you start on a very mountaneous world - cannot recommend for new players -, the existing tank model may be kinda worthless and hinder you getting advanced ranged models.
The logistics hell this game is IS the fun part! - Maerchen, 2020
The good thing is, we have all the information in the reports. The bad thing is, we have all the information. Maerchen, 2020
Came for SE. Will stay for SE.