Oh yes alxnjord! you’re right, you also get there that “sirvar” instead of “silvar”. In other parts of Andalusia they even lisp, so they never pronounce the “s” sound, they always use the “z” (th). It can be hard sometimes, ever for us, to understand some of them xD
alxnjord, I agree that I should study the pronunciation which will be most useful to me. I have a far greater opportunity to speak with speakers of Mexican Spanish than from any other region, therefore while I will strive to understand with ease any pronunciation, I will try my hardest to mimic the accent of Mexico.
Personally I really don’t like the European Spanish ‘th’ for the s sounds. I really don’t think it matters what accent I try to use or listen to anyway. I’m sure I will mix them all up and sound like I come from 7 different countries but as long as I make sense then that’s all that matters! 
I’m sure over time I will naturally start following a particular accent. Probably the one from the people I end up speaking with the most.
I must say though. After 18 months of tearing my hair out over German, I am so happy that I’m learning a language now that actually uses common sense! 
I didn’t find the “th” to be very hard or weird. And now it is my default when reading or pronouncing words. I found it intriguing.
Much to the tease of my latino friends.
But I guess I purposefully chose to emulate Spain.
I will travel this world, you’ll see. Europe fix yourself up and make yourself pretty for me, because I swear it, I’m coming for you. Watch Out.
Also…
((I have a Mexican friend who learned British English))
At the bottom, shows you those paragraphs, and the audio from all those speakers saying them.
To me its like a tongue twister.
New research on language speed:
http://www.time.com/time/health/article/0,8599,2091477,00.html#ixzz1XMJhQz00
A very different theory from the ‘mora/stress’ timed idea.
It depends on where you are from. I’m Puerto RIcan raised in America but have been around Spanish all my life and from my experience I can tell you from my experience that I find Spanish spoken from Spain to be one of the fastest sounding varieties. I myself have a difficulty in understanding them sometimes. Cubans speak a similar variety of Spanish from Spain but with a Caribbean accent.
In the Caribbean, as a whole, we “eat” our syllable ending ‘s’ (so do a lot of Central and South Americans), for example:
esperar- to wait => e'perar.
It’s tricky to pick up on plurals, but if you listen carefully you can tell that the vowel becomes lengthened, or there’s almost a type of glottal stop after the vowel, for example:
la mariposa (the butterfly) => laaah mariposaaah (las mariposas)
Or “la mariposa” becomes "la’ mariposa’ " (with a type of glottal stop)
We also "eat’ most ‘d’ sounds, but so do a lot of South/Central Americans:
Mitaah (instead of 'mitad' - "half) ,"Casa eeh maria" (instead of 'casa de Maria' - Maria's house)
In Puerto Rico the trilled ‘rr’ has different sounds, it can either be a ‘hacked h’ sound like in Arabic:
Carro (car) => cahhhhho or the 'trilled rr' turns into an Arabic or Hindu trilled 'rr', which is pronounced with the tongue curled like a cup and isn't as strong of a trill as other Spanish countries.
In the Caribbean there’s also a lot of nasalized vowels like they would have in Portuguese, for example:
Ven (come, from verb 'to come') => ve (the 'e' is nasalized and the 'n' sound disappears)
Son (are, from verb 'to be') => so (the 'o' is nasalized and the 'n' disappears)
Canción = canció (without final 'n')
Or these words could be pronounced similar to ‘veng’, ‘song’ or 'cancióng) (‘ng’ sound in ‘sing’)
Some word ending disappear altogether and other words are made up from two or three words combined:
'Para' (for) become 'pa'
'todo' (all) becomes 'toooh'
The experession "Ven para acá" would be pronounced:
Be (nasal 'e')/or Beng pa'cá. (meaning 'come over
here')
I think all these features combined make it appear like Spanish speakers from the Caribbean speak fast but they actually don’t, it just seems like it. In fact we may speak a bit slower (except Cubans) especially because the ‘accented vowels’ and the missing ‘s’ and ‘d’ sounds cause the vowels to be pronounced longer than normal which in turn slows down speech especially if you have two possible long vowels in one word and one is obviously accented or stressed.