I've stayed in both and I really like the Le Meridién. Have stayed a number of times, and have gotten major upgrades on a few occasions like to corner two-room suites with an invitation to a dance performance as a bonus or a gift of a Le Labo candle (retail about $80). The very immediate vicinity on Las Ramblas is super-touristy, but the location is extremely central. It's an easy walk to Passeig de Gracia, El Born, the Barri Gotíc. Also if you take the Aerobus from the airport, which to me is the best way to get into the city, it lets you off a 5-minute walk from the Le Meridien in Plaça Catalunya.
That said, the Four Points is perfectly fine. It's in a quieter neighborhood, business district on main streets and residential otherwise. Short walk to the beach.
LM is more luxurious as one would expect given brand differential, but it's up to you whether it's worth the extra 24K points.