I dont have one and have never seen one, so I am of limited use.
But I will say, I dont like MFG's of implements that dont list detailed specs.
The TSC unit, I know used to be made by tartar. Their standard duty stuff had 14ga top and 11ga (1/8") side bands. If the 4' cutter you have happens to be their "sub-compact" line (usually painted orange instead of yellow), its only got 13ga sides.
There is limited info on the LMC. Just what does "6 inch channel sides" mean? Is it just 11ga rolled to channel configuration? or is it actually a common channel iron size?
One of the important specs IMO when it comes to a cutter, especially if you want it to cut grass well, is blade tip speed. Neither LMC or TSC list that tidbit. If they would at least give gearbox ratio, one could figure it.
I know that my cutter with 10,200fpm blade speed dont cut grasses well at all. My cutter that is 12,400 is better, but not great. Havent tried a cutter up in the 15-17k range, but am currently shopping myself.
Is there a reason you arent considering Landpride, woods, bushhog, etc. Any of the well know brands? Not likely to find someone with much experience with the lesser know brands. Heres some comparisons..
Brand/model.................Weight.........Blade tip speed..........Deck thickness...........Side thickness........gearbox HP
Landpride RCR1260.........478#.............16,536.......................12ga..........................???..................50HP
Landpride RCR1860.........599#............16,363.......................10ga.........................10ga..................???
Woods BB60x...................604#.............14,355......................?..................................?.....................65HP
Woods HC60.....................534#............14,355......................11ga..........................11ga................65HP
Bushhog BH5....................491#............15,497.....................12ga....................8" channel, 10ga........60HP
Bushhog BH15..................636#............14,369......................11ga..........................11ga..................45hp
LMC Andy 500.................?????............?????........................12ga.....................6" channel???...........40hp