I am a big fan of acoustic guitar simulators, so, I had along the time the next ones:
1. Behringer AM100 - without true bypass, plastic enclosure and some hiss, but cheap...so if you play as me only at home it's the a very good solution: a few dollars and no headache with DIY-ing
2. Boss AC-2 - without true bypass, well made, but not so cheap...as almost any Boss pedal it sucks the tone (on my setup the combination Boss-->EHX it's a disaster)
3. Nabo's clone of AC-2 - you can made it true bypass, no buffers, better controls than Boss (even in my build a pot has only a little effect), enough components to solder, but, what's worst, the PCB is huge...I sold it because I can't find a proper enclosure for it (I think that it must to be something like 3 Boss stompboxes in a row)
4. Mark Hammer's Woody - true bypass, half components than Nabo's AC-2 clone (I've built it in 2 hours or less...), very good sounding, the controls are very effective (don't use a dual 10K pot...use 2 different 10K pots for top and bottom)...the only little problem is that it needs 2 batteries or a bipolar power supply (I've read that is a version with a single battery, but I couldn't find it).
So, after my taste, the winner is Mark Hammer's Woody (thx a lot Mark again)...