I know I am going against the grain here, but it is important to point out that he simply has more upside. I would even gamble, that if we look back in 5 years, this discussion will probably seem silly. Sure Mench is a solid power threat, and even has a better K/BB%, but I would rather have Lane going forward.
Their BA's will be similar, around .275-285 year in and year out, but Lane will get you slightly more HR's and will probably be in a better spot in the lineup for years to come. He could easily be part of the R/L/R combo in either the 3 or 5 spot for the next decade with Berkman and Ensberg. Mench, if he even stays in Texas as was pointed out, will be in the 6 or 7 spot for the Rangers. Especially with Tex, Blaylock and Soriano there.
Plus, and this may not matter a ton, but Lane has more speed.
and something that is forgotten ... Allot of Lanes early season struggles can be attributed to the simple fact that Houston left him sitting on the bench for the last two seasons. Once he became used to consistent playing time again, he took off, and showed us what we were promised for years.
I'll take Jason ... and by the sound of things, a few rounds after you guys take Mench