I have both, and though I do like the MG, I find I prefer the Connolly. Everyone says it is kitschy and childish - but guess what? It was Connolly's then 17 year old son, Peter Paul, who did the paintings for the deck. Not really childish if you regard his age, and his talent was, I thought, fairly good.
I read publicly with this deck for several years. I always offered a choice of 6 decks to people, and this is the one they always picked! It is not offensive in any way, and if you are reading for people who are Christian, they may be much more comfortable with this than the MG. I always thought it gave very straightforward and precise readings.
The fact that the Death card is called Transition, and the Devil card is called Materialism, doesn't take anything away from the cards. And in fact, the public seemed way less put off or frightened by them. In fact, I thought it was nice to have a Death card that didn't have a skellie in it!
and the title change illustrates the meanings of the two cards quite well.
One of the benefits of the Connolly is that the colours used in each card give you an immediate idea of the "feel" behind the meaning, and when you are scanning a large spread, those colours jump out easily and gives you an eagle's eye view, so to speak, of the reading. Gives a good overview, an immediate visual impact.
The books that are affiliated to the deck (the basic and the journeyman's guide) are very well written, and if you are Christian the references will not bother you. Connolly is Catholic, and so she often touches on that, but her books are really instructive, and contain some great spreads, including one that uses the whole deck.
If you buy the Connolly, try to get the Belgian printed one, the cardstock is lovely
ETA one of the things I HATE about the MG is that the Death card's skeleton has a priest's "dog collar" - or so it looks.
ETA x2 - the only Christian vibe card in the Connolly is the 9 of Cups, featuring Jesus at the last supper.
