You are missing one big thing here and you will notice it after my calculations

I can only compare limits up to 0.5/1 with these two sites, so let's do that...

FL SH 0.5/1 Mansion:

21449 hands

18214 MCP collected

85 MCP/100

637,94$ rake paid

2,97BB/100 rake

FL SH 0.5/1 PokerStars

29856 hands

5131 VPP collected

17,2 VPP/100

731,36$ rake paid

2,45BB/100 rake

So let's take 285$ PokerStars' bonus and 500$ Mansion's bonus.

For 285$ bonus you need 25,000 FPP.

As gold you would need 12,500 VPP (25k/2), which is

72674 hands.

In meantime you generate 1780$ rake.

For 500$ bonus you need 250 000 MCP.

For easier calculation, let's assume we also play 72674 hands in three months.

72674 * 85/100 = 61773 MCP with monthly boost: 2,5*61773 = 154432 MPC

+Three month's boost: 105 000 MCP

= 259433 MCP

= 104% 500$ bonus = ~520$ bonus.

Now you will say... WTF, you get 235$ more at Mansion!

Guess again

After 72674 hands, you pay 2158$ rake.

PokerStars:

-1780$ rake + 285$ Cash Bonus = -1495$

Mansion:

-2158$ rake + 520$ Bonus = -1638$

So at PokerStars you have 143$ more after three months of playing and 72674 hands.

Similar story at 0.25/0.50... (won't go into details here)

FL SH 0.25/0.50 PokerStars

12213 hands

155,25$ rake paid

2,54BB/100 rake

FL SH 0.25/0.50 Mansion

22044 hands

370,06$ rake

3.38BB/100 rake paid

After 100 000 hands:

PokerStars: 1270$ rake paid

Mansion: 1690$ rake paid

You'd have to play 6 months straight at Mansion to get even...