Can someone please demystify umeboshi for me?

I'm very interested in trying umeboshi, but the last time I went to a large Asian market to buy some, there were dozens of different varieties...and all of them described in Japanese, which I do not read. Can someone point out a good brand or type to try? Some I saw were dry packed, others were sitting in liquid. Some looked firm and wrinkly and others were plump and looked soft. I'm just so confused. Is there one in particular that's just very popular and/or a good choice for an umeboshi newbie?
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