Sinister Portal or Ambrosial Portal - Which Should I Get?

It's really too close to call.

The Sinister is more powerful but has less attraction and a negative cheese effect. The Ambrosial has less power but higher attraction and a lower chance of spoiling your cheese.

Stats

Obviously it's not *quite* that simple, so let's compare stats with each base, shall we?

For the Wooden Base:

Weapon	Power	Power bonus	Attraction bonus	Luck	Cheese Effect
Sinister Portal	1113	5%	0%	0	Fresh
Ambrosial Portal	1060	0%	5%	0	Extremely Fresh

For the Wooden Base with Target:

Weapon	Power	Power bonus	Attraction bonus	Luck	Cheese Effect
Sinister Portal	1155	5%	20%	0	Stale
Ambrosial Portal	1100	0%	25%	0	Fresh

For the Stone Base:

Weapon	Power	Power bonus	Attraction bonus	Luck	Cheese Effect
Sinister Portal	1351	15%	0%	0	No Effect
Ambrosial Portal	1293	10%	5%	0	Very Fresh

For the Explosive Base:

Weapon	Power	Power bonus	Attraction bonus	Luck	Cheese Effect
Sinister Portal	1458	10%	5%	0	Very Stale
Ambrosial Portal	1391	5%	10%	0	No Effect

For the Dehydration Base:

Weapon	Power	Power bonus	Attraction bonus	Luck	Cheese Effect
Sinister Portal	1313	5%	5%	4	Extremely Fresh
Ambrosial Portal	1250	0%	10%	4	Ultimately Fresh

For the Polar Base:

Weapon	Power	Power bonus	Attraction bonus	Luck	Cheese Effect
Sinister Portal	1409	15%	0%	4	Extremely Fresh
Ambrosial Portal	1348	10%	5%	4	Ultimately Fresh

For the Birthday Cake Base:

Weapon	Power	Power bonus	Attraction bonus	Luck	Cheese Effect
Sinister Portal	1392	16%	5%	0	Stale
Ambrosial Portal	1332	11%	10%	0	Fresh

Closer Examination

Based on those stats, we can draw this conclusion: you're going to gain approximately 50-60 damage by using the sinister portal, for any base. Is that worth the 5% drop in attraction along with the 2-level drop in cheese freshness?

Well, what are you looking for? Sinister Portal will catch the mouse a little bit more often, while the Ambrosial Portal will give a greater chance of attracting mice, along with making sure cheese doesn't go stale.

Most people would say Sinister. Portals are typically used in the Mousoleum, where encounters are frequent, but captures are unfortunately not. That little boost in attack makes a difference. However, the two traps are so close together that it really comes down to preference.