Effective US-Soviet aircraft pairings?

Some countries have both US and Russian/Soviet aircraft in their inventories, often they are the same class of aircraft. are these pairings effective and meet the needs of their Air force well, or are in some cases, a logistical nightmare and better served with fewer types?

Indonesia
Su-27/30MKK and F-16A

Poland
MiG-29 and F-16C b50/52

India
quite possibly Su-30MKI, MiG-29, and F-18E

Malaysia
MiG-29, Su-30MKM, and F-18C

Venezuela
Su-30MKV and F-16

European pairings

Hungary
MiG-29 and Gripen

Peru
MiG-29 and Mirage 2000