Even more on Early Shabbos
Lately I have seen that some people have started doing the following. Mekabel Shabbos right after plag, then going home and eating the meal, and then later (around 9PM) coming back to shul to daven maariv. The advantage of this is that you get to be יוצא krias shema in maariv with a minyan, as well as count sefira at the proper time.
However, there is a downside to this as well. The Gra in the מעשה רב says that you should not eat the first meal of Shabbos beofre you daven maariv.
RYBS also held like this and he explained his reasoning as follows (see Nefesh Harav and Beis Yitzhak 1992 p. 60). The kedushas hayom of Shabbos is not mechayev you in simcha and therefore oneg shabbos is a side mitzva and not part of the identity of the day. Shabbos is supposed to be a day dedicated to Hashem. Therefore he said, to eat the meal on Shabbos you need a matir, the tefila. Because of this each meal is preceded by a tefila. He pointed out that it is mashma like this from the Rambam as well. The Rambam writes (Hilchos Shabbos 30:10)
יתפלל אדם בשבת שחרית ומוסף בבית הכנסת, ויבוא לביתו ויסעוד סעודה שנייה, וילך לבית המדרש יקרא וישמע עד המנחה, ויתפלל מנחה; ואחר כך יקבע סעודה שלישית על היין, ויאכל וישתה עד מוצאי שבת
The Rambam describes how first you daven and then you eat, this seems to be the correct way of doing things.