What do you prefer: a trial period or a free tariff plan with limited features?

For Price2Spy 2.0 , we are using a free 30 days trial, and it turned out to be a good decision. For BotMeNot, I am planning to offer a very basic version that would come at no cost for the users - since the app will work on credits. We'll see which one of these strategies will turn out to be better. I think that both have their advantages, it just depends on the type of the product.

It depends on service or product, do prefer a combination of free and premium FreeMium!

I prefer trial definitely! Because you get full experience.

I think the best option is a combination of both: add a free plan, but allow the user to test the full feature list for X amount of days. After the trial expires the user can decide if they require the extra functionality or not. Depending on the software type, even the free users can end up landing payed users by spreading the tool. Depends on the service type, but from my point of view this would be the best option.

I prefer free tariff plan with limited features.

Depends. I can think of many products where I would want one or the other. Or a mix as suggested by @iscu_andrei. Assuming you already know users want your product from previous user research I think the best approach is to do a (new) series of interviews, where you have explained exactly price, length of trial period and what the limited features are to the interviewee. And then code responses as to what will make the interviewee most likely to 1) sign-up and 2) not churn on your product. Alternatively just launch with everything free, and then experiment with different subsections of your userbase (if you tech allows) where you turn features off in return for payments, and see how many drop off. Or advertise different trial period lengths to different user groups (for instance by geographic market) and see what the response is.