1. It is more paperwork and more money. You must provide sufficient evidence of a bona fide marriage...again.
2. After the conditional GC expires, you have to keep up with the original extension letter. Some people have had issues when renewing driver's licenses, boarding planes, etc.
3. If your case is still not processed after the extension letter expires, you must try to get an appointment or a mailed ADIT stamp from USCIS. Some people have had a LOT of trouble getting USCIS to cooperate.
4. Status remains intact. However, maintaining evidence of status has been an issue for some folks. See #3 above.
5. Only about 1% of I-751s are actually denied.
It took USCIS 44 months to process my wife's I-751. We had a rock-solid case with no RFEs. Your miles may vary, of course. My point is that avoiding Removal of Conditions will eliminate a LOT of hassle and extra expense. Of course, sometimes, individual priorities override the inconvenience. In the case of the OP, I would seriously consider waiting to enter. Just my courteous opinion. Good luck on your personal journey.