I came to Forge Engine from mostly d20 systems so there was a definite learning curve, but not in a bad way.
I like that the d10 system is (mostly) opposed - having played one d10 system where 6 is a always a succcess this is better.
The energy system is more complex than most other systems but has several significant pros.
Defense is not static so unlike strict turn systems you just don't throw everything you can into your "turn" and be able to rely on static defences.
The need to hold onto energy to react to adverseries actions makes turns more realistic and your actually won't know that your "turn" (decision making wise) is over till it's over.
Externalities (keyword) allows the GM to reward clever play, and as it is at the GM's discretion it is simple and quick and there are no rule arguments, "The DMG says it is 50% cover so I get +4 not +2!"
Get your head around the energy system and the game will flow.
Practical advice - get two different colours for your d10's and use one for energy (Red) and one for bonus dice (white)
Combat wise having a set pool of d10 for a weapon whether it is prehistoric (rock) generic (knife) or advanced (rifle) is simple, intuitive and easy to understand, eg, The guy with the shortbow has to spend 3 energy to get 2 attack dice (takes a bunch of effort) but me with my 44 magnum I only have to spend 2 energy (its mostly the gun doing the work) and get 4 dice (very big bullets!) and dice pools are very obvious/intuitive - Having an absolute fistful of dice is a winning feeling much much betterthan rolling two d10 and crossing your fingers.
Last and definately not least the system excels where different worlds collide, eg, pPost apocalyse where shortbows often fight handguns, Horror where magic goes up against modern policing methods, or simply that many of the skills translate accross genres eg, Medicine works for a caveman shaman (trepanning anyone?), a 17th century physician (-2 dice for using leeches?) or a 21 century surgeon (many bonus dice from technology)
[5 of 5 Stars!]