I have found that Tiger figures range from average to terrible. For the Spanish American War range, the standard US troops are very clumsy sculpts (poor detailing, with overlarge hands and huge rifles that make any riflemen totally incompatible with other manufacturers).
However, although I use Redoubt's Boxer Rebellion range for the core troops in my US Marines, I do use some Tiger items to fill in the gaps (deck-mounted gatlings for my boats, landing gun for my marines, beach landing signalling team and, on the painting table, some artillery with crews). With a good paint job, the Tiger figures don't look too bad if you avoid mixing them in units with other manufacturars and just use them for specialist units/additional command figures.
A good example of the overlarge 'boxing glove' hands on some Tiger figures:
http://leadadventureforum.com/gallery/5/164_15_01_10_12_03_43.jpgUS marines landing gun - although the figures aren't too hot, no one else does one of these guns and the finished unit looks ok alongside the rest of my marines:
Redoubt machinegun team with Tiger ammunition carrier - showing that, although most Tiger figures are poor sculpts, they don't look too bad alongside other manufacturers' figures if you are careful as to which ones you choose:
Overall, I would recommend using other manufacturers where you can for standard troops. Use Tiger for their nice artillery and equipment, which includes many items you can't get elsewhere.
The current project on my painting table is a US Army artillery pool to support my marines - Tiger mountain and field artillery, with crews and mules. Also a field telegraph set (see what I mean about items that no on else manufactures). I will post pictures when this lot is finished some time after Easter.