Basic point is that they will differ in coverage area i.e macro coverage up to 400 meters to 2 km while femto cells provide a coverage 50 to 100 meters.
So all functional difference will come with respect to coverage area only i just taken some of points which will clarify the difference.
1> Management & Installation :- Macro need more procedure so usually done by operator where as femto cells and be installed by end users and it is also semi automomous.
2> Frequency Planning :- For macro cell we need to do central frequency planning to avoid interference but for femto cell as coverage is less so can be determined locally.
3> Signal Quality :- In macro we need strong outdoor signal quality if we are inside a building , but in case of femto as its range is less you can get better signal quality due to its concentric nature.
4> Expensive from user point :- If a user using macro cost for the user will be less but if he installing femto in his building cost will be more with respect to user.
5> Number of user support : - Any way femto has less frequency resource so no of user support will be less.
6> Spectrum Technology :- In case of femto as the range is less so if we are using TDD it will be effective as less chance of propagation delay, but in case of macro as the coverage is more in long range transmission so in case of TDD time mismatch will happen due to propagation delay.
7> Power Consumption :- In case of femto it will consume less power and in case of macro it's more.
