General thoughts + impressions having played B&S, TERA, and BDO.

General:

• Combat system is not nearly as good the others. It's a somewhat awkward mix of tab-targeting + TERA-style action combat. It doesn't really feel that bad in practice, and it's definitely still a million times better than traditional tab-targeting, but it's not quite there relative to B&S or TERA in my opinion.
• Story can be kinda cheesy but the dialogue's pretty decent actually. The story is written by a decently well-known Chinese author. That said, as someone that can read Chinese, the quality of the translation varied greatly in the CBT: some of it's surprisingly well-done and some of it looks machine translated.
• Crafting system is pretty involved and useful right from the get-go really, but has an ArcheAge-like system where it costs "physique" and "intellect" to gather mats + craft. These are resources that automatically - and sloooowly - replenish over time when you are online or offline with a premium membership.
• Many different avenues for competition with daily/weekly rewards, but they typically only reward the top 3-10 in a server, so rewards don't scale very well for an MMO. (There is, for example, an hourly system for finding treasure but only one person each hour can find the treasure.)
• Very community-oriented. Strongly encourages you to be in a guild and play in groups. Even activities that can be easily done solo reward you for playing in a group by boosting rewards when you're in a party.
• Directly rewards advanced players for helping newer players. There are a few types of mentoring in the game: a sophisticated mentoring system where you literally take on a teacher-student role, an automated system that gives you points for buying gear-crafting mats when you party with low level players for dungeons, and a sidekick mode in expert dungeons where you can bypass your raid lockouts to help others run dungeons (by foregoing personal rewards).

PVE:

• Content is very dungeon-oriented. Party-finder at the moment works spottily at best and wasn't used much in the CBT. People pretty much formed groups through world chat.
• Classes are pretty balanced for content. This is the only MMO I've ever played where I actually saw groups having trouble finding DPS classes for their parties! With some of the easier / daily content, you can even run full-DPS parties for, which I did not that infrequently during the CBT.
• This is not one of the games where you need to rush to the endgame because that's where all the content is. The leveling process is very gradual (Chinese players aren't even at level cap), and it's the best experience I've had leveling since vanilla WoW. The game is even designed such that you'll want to cap yourself at certain levels until you have the gear to proceed. (Monsters in certain venues scale every ten levels, e.g., 40-49. The game thus has a system implemented where starting with level 39, you have to manually proceed to the next level once you have the required exp, the system saving all your exp for you until you decide to do so. Players thus choose to stay at levels ending in 9 until they're ready to transition to the next phase of their progression.)
• You don't need to rely on RNGesus for that lucky drop followed by the lucky roll. Dungeon drops are still very good, but the primary source for gear (outside of PvP) is by crafting gear through NPCs. Mats are obtained either via player crafting or by using points and currency earned by running dungeons. This means that you can make guaranteed progression toward the gear you want just by making to sure to do all your daily and weekly activities.
• There's a limit on how many times you can do each activity each day and each week. These daily activities are very important, and missing out on them will set you far behind. The limit will likely also be a source of frustration to some hardcore players, but there's a TON to do in-game nevertheless.

PVP - I can't say too much here because I was on Server 2 and group PvP wasn't working for us:

• Emphasis is on group-based combat as opposed to 1v1. Arena is 3v3 with multiple large-scale group PvP venues such as 10v10 & 20v20 battlegrounds, guild wars, open-world PvP for world bosses, etc.