I've recently bought a macmini, and i need a tool to write songs, i have a pc with a daw and all my plugins installed....but i want to use to the mac too for a different approach....i was looking into reason or logic cause they have a big sound library, i'm interested in instruments to play, like electric pianos, bass, synths, etc, seems that logic has a big library but reason does too, it's quite more expensive than logic....Has anyone here been able to compare the sound libs in terms of instruments to write tracks?...the demo's at logic's page sound way better than some reason instruments imo.

They address different kinds of musical production. I personally find the sampled instruments in Logic to be more realistic or robust for use that's not buried in a mix. There is a much greater variety of sound generators in Logic, too (number of synths). But Reason is a good product too. I have both. I use Reason for crazy sound design with the routing abilities and I use it for rebuilding my old MOD/tracker music (the samplers are very easy to work with, compared to Logic's sampler). But Logic has way more utility in effects plugins. Probably I'll export audio stems from Reason to finish in Logic.

Does that help at all?

of course it helps, thanks!
I just wanted to know if the instruments included in Logic were "better" in terms of "realism", for sound design and production i think i'll keep using the pc!

Logic will allow you into the world of Kontakt, and if it's realistic instruments you're after there's nothing better. The core library is usable but the 3rd parts libraries are outstanding.

I'm already using kontakt with my pc, i just want to give the mac some musical use

How about starting with GarageBand. It is easier to learn and you can move up to Logic anytime because the projects are compatible with Logic and so are the Apple Loops, Instruments, plugins, Plugin Settings and ChannelStrip settings.
You can buy the MainStage app for $29 to get all the 6 JamPacks Loops and instruments (20GB !)

If you need help with GarageBand, it happened that I just released a new book for GarageBand (GarageBand 11 - How it Works) that explains everything in great detailes (sorry, shameless plug).

Thanks for the offer, but i think garageband is bit limited for me

If you're asking about realism, yes, Logic instruments beat Reason, IMO, for non-synth sounds.

GarageBand is actually quite a good quick songwriting tool. I use it similarly. You can move the projects to Logic once they need heavy duty production.

You are right. It often gets a bad rap as a toy thingy. But I would challenge anybody to explain the Flex Time feature as a toy, or using GarageBand with Reason or Ableton with ReWire.

As long as you know its limitations and work inside that, it is actually pretty powerful.

Garage band is a great starting point I have to second that. The other thing to keep in mind when upgrading to new DAW is the workflow and what you plan to use it for. I love Logic myself, but I also use Reaper more and more now, as it has proven over and over to be extremely stable on my system which Logic was not.
Reaper doesn't give you plugins like Logic, but they don't cost what logic does either, so you can than hand pick the plugins you need else where and make the DAW with plugins you need.

I think you can still find copies of Logic Express on the web for $100. It was discontinued and is no longer supported by Apple, of course, but I've heard that it works well with the complete Jam Packs that are included in Mainstage for $30, so, depending on what OS you are on, that might be an option. Maybe worth checking out until you can make the move up to Logic Pro.

Logic beats reason for a writing tool as it is much more musical (IMHO). There is no doubt that you can write great music with virtually any DAW, and Reason is for sure included in that, it's just that Logic is better sounding, and more robust...and I hate to say it, since it is an Apple product, will safely be on the forefront of the OS march in terms of updates and native plugs.

And for $199, it is hard to beat. Even though I am biased as a logic user for many years, I have worked in many of the other DAWs, but as a complete writing/production/mixing tool...I always come running back to Logic.