Bob,
Either in kit or ARF form, the LT-40 is hard to beat. I built the kit with my son and thoroughly enjoyed it. Yes, it does take additional time compared to assembling an ARF but, if you follow Sig's excellent instructions and RCKen's excellent build thread, you can't go wrong.
One more advantage to building from the kit - it won't necessarily look like everyone else's LT-40 ARF at the field.
Please review the photo/thread I put up a few years ago documenting my son and I soloing on our LT-40. I still cherish that day...
http://www.rcuniverse.com/forum/m_3477988/tm.htm