One precaution I would take with 3-wheelers is to check the width of the back wheels. We were hesitating between Herqules and Quiny and in the end we went for Quinny SX.
It is quite good in the sense that it is very easy to maenouver (360 degree front wheel) and light with the seat unit (but much less when adapting the carry cot). It is also probably shorter than other 3-wheelers. Globaly I like it and find it very easy to use in helsinki center and shops (I don't know about nature tracks). The negative points are the following:
- ridiculously small shoping basket.
- adaptable carry cot is a bit narrow (after 1,5 month only!) for our baby who is sleeping on her stomach, and is quite heavy.
- Although the pram looked quite compact to us, it appeared that it is too wide to fit in the old trams

but otherwise, the compactness is good and I think better than the Herqules.
We prefered this Quinny compared to the other models of the brand because of the bigger size of the front wheel.
You can check quiny products on there web site:
http://www.quinny.com/
You can also see the SX in stockmann.
It is a bit cheeper in suomen lastenvaunutukku (
http://www.suomenlastenvaunutukku.fi/index.htm) which is in Vantaa but they seem to be mooving or openning a new shop in espoo.
We also found some Quinny stuff even cheeper on a finnish web shop:
http://www.leppakerttu.fi/index.php. These guys seem not to sell anymore the Quinny prams but it might be worth to ring them and ask, they were very helpfull to us.
good luck for your pram chase!