Although I'm definitely not a guru when it comes to sambo jigging... I've certainly caught my fair share of decent pelagic (tuna etc.) up north. My preference would be more drag less line. (they need to be stopped soon, or you're in for a long fight.)

personally cant see 6kg of drag cutting it for sambo jigging myself.

But will be following this thread to see what more experienced sambo jiggers say

Edit: don't know the specs of the Daiwa Blast but I think it had more than 6kg drag and was somewhere in your price range.

...I'm assuming you're going to use proper PE jigging line, Matt? The reels' line capacities may be based on normal braid (or, gadzooks, mono!) which means that you'd fit more PE line on there than what the reels say.

I'm not a sambo jigging guru either, just might be something to be aware of while you're making your decision, and it would also strengthen the "more drag" argument! 

Edit: Just googled the bigger seagates and the line caps appear to be stated in PE. I'll go back in my box, now!

Drag, 200m of line is still a fair whack and on the boat you can always chase the fish

 I've used my big Okuma Salina a couple of times and that's performed floorlessly, good bang for bucks reel. It's got about 400m of 50lb whiplash and has plenty of drag, about 20 kg if memory serves me correctly.

if u only jigging sambos

get an overhead

saltist (i use and  ld 40) will piss over any spin type reel when it comes to stopping sambos

they are cheap well made reels

The Biomaster is a vastly better reel in my opinion, screw in handle, better AR bearing, better handle knob, the only thing the seagate has over it is a wider line roller! Another option and one that will give you a slightly larger reel for better money (and better quality imo) are Caldia 4000s, whether you go the SHA or the new model depends on what gear ratio you want, I reckon the Daiwa Blast 4020 although a great reel is too high a gear for pulling deep lugging fish and has too large an arbour on the spool reducing the line capacity.

go for drag. I catch them on 30lb using 10lb drag settings, but I realy should use 50lb and 16lb drag settings. My goto reel for sambos is an Alvey (I don't get the most fish but there you have it)

What realy matters is the anti reverse mechanism. I blew up a Shimano TSS4 spinner a few years ago fishing fifty lb line and 15lb drag settings

Fin Nor Leathal 100 at $140 should be unbeatable for Sambo jigging. Load it with 50lb, wind the drag down and hang on.

If you are mainly targeting sambos I would go the next size up in reel for Shimano. That would give you your 300m of PE3. As far as balance goes depends on your rod choice.
But if you want to stick with a 5000 (bio master, sustain, saragosa in that price)go a high quality PE 2.5. This could still be a 50lb plus line with a 300m capacity with plenty of drag pressure.

 While i cant comment one the new hyper seagate i can comment on the older model .. its crap .. i destroyed it in under a year demersal jigging pe1.5 .. i did catch the odd small sambo on it but mainly dhufish on plastics . Id hate to use it as a proper sambo reel. both myself and my main deckie bought them at the same time and they both died in less than a year.

Just ordered a Caldia 4000, getting upgraded knob for it. 8kg drag & fits 300m PE 2.5 ( daiwa tornument 8 40lb) $413 all up, dont want to go over board its only going on a PE 2-4 Gomoku

I havnt used either of the above reels. But if it helps i have got 300m of Saltiga tournament P.E3 on my 5000 stella.

I think that is about 56lb line.

The Biomaster SWA has a 10 year warranty so should be long lasting if used with-in it's capacity :)

but only comes with 11 - 13 Kg Drag range and yes I'm not making any claims either, just can't understand if a fish weighs more than 20 Kg why it won't damage a reel with only 13 Kg drag when your trying to get in up ??

If you want a 'spin' type reel check out the Finn-Nor LETHAL in this LINK: www.finnorfishing.com/LethalSP.html  at about $150

Can be spooled with 300 yds of 100 lb braid and has 45 Kg lock down drag- now this reads good to me :)

But if I'm understanding the information all wrong - please tell me 'nicely' as I really have no idea at all - I'm just the messenger :)

AND.... it will assist me to check out some reels for my own use

I've a Fin-Nor Off Shore level wind reel and love how smooth it is with a retrieve that is responsive and not over priced

and ... a Fin-Nor Firepower FP7000 Spinning reel too

Found these Lethals while looking for a new (small) spin reel for myself :) :)