I think the landscape is better in defense. In TFTD all you get is corals (which makes for a very boring landscape IMO + most of the maps from memory looked identical).
Also I suggest when you do your map sweep don't sweep buildings room by room, instead use your heavy gunners (rocket launchers to flatten any buildings); much safer method.
Use 3 man teams (i.e x2 scouts working together covered by x1 sniper). I prefer 14 men crew (6 scouts, 3 snipers, x2 heavy weapons, x1 grenadier, x1 ammo mule, x1 officer)
Each 3 man team uses x2 scouts to leap frog each other with one being resting scout while both are covered by the third man- a sniper. Basically when sweeping the map you want to move(the resting scout), only 1-2 squares (you'll be able to do more as TU's improve), forward then kneel (this will leave most of time units free for reaction fire); the 2nd scout might move 8 squares forward (if an alien is not discovered), then move 8 squares back and kneel (so he ends up next to resting scout). This way any alien not discovered will in most cases need to move at least 8 squares to get line of sight on the scouts which means the resting scout will usually react fire( particularly as TU's approach 80 and reaction stats approach 60+; you will always react fire). This system dramatically reduces casualties. I am currently at month of April and most of my scouts have reaction stat over 70 now (i think my weakest scout has about 62), and the aliens pretty much cannot get near us due to reaction fire.
If you apply the mod in the .ini -Heavy explosives can also now breach ufo walls so take advantage of this. They are also good to clear buildings. They can be thrown like grenades but are much better. So make use of your Grenadier. HEs are much heavier than grenades so make sure your grenadier has a good starting strength (+40) stat- so he can actually throw the damn thing. as his strength improves he will become very valuable.
*NOTE: if you want you can improve damage of heavy laser by typing following command into extender .ini under OBDATA (I set my value to 120 but you can use lower value because I am finding 120 is a bit OP)
Heavy Laser Damage=120
Remember that with heavy laser you can target up to x3 aliens at once if you use burst mode; so make use of this method. It will take up most of your TU's but since snipers spend most of time stationary in kneeling once a good position (whereby the sniper can cover his scouts as they sweep the map), is found it doesn't matter much.
TIPS:
1. Use smoke grenade and deploy it on ground in front of Skyranger latch door. You actually move out of Skyranger on turn 2 under smoke protection; this method prevents aliens from throwing grenades as your first guy leaves the Skyranger or gets shot right in the head by an unseen alien just outside Skyranger. Albeit keep it mind any aliens detected/seen while you're still in the Skyranger (before having a chance to deploy),should be shot immediately.
2. The two guys at the back of the Skyranger can actually look through pilots cockpit windows if you turn them around; this way you can see whats behind the skyranger prior to deploying your guys.
