I have really enjoyed my flights on LAN, have not used Taca yet. My last trip on LAN was on a 767 from MIA to EZE, had two seats to myself in economy, watched Garden State twice, great alcohol service. NB was hit and miss, was on an A340 from EZE to SCL which was great. My seat SCL to MIA was too near the restroom and did not recline, also the overhead light had an issue and would not turn off. Flight attendant attempted to rectify with no luck.
Also keep in mind fares are cheaper on Lan.com when you do it in the spanish version, sometimes very significantly cheaper!
Adam