Talk me into a Fenix over a Venu as a first timer :Newbie

Be aware that the Garmin devices are true sports watches with some smartwatch functionalities. Not that you're getting disappointed in case you see someone with an Apple Watch of Samsung.

That could be a disadvantage for the smartwatch guys, but the sporting functionalities are clear on the Garmin side.
My wife is using a Vivoactive 4 which is the Venu, but different display while i am using a Fenix 6X

The Fenix 6S would be an option for you and your small wrists. However even if it's small it is still thicker than the VA/Venu, that's wat you need to consider as well.

The 6S has a little longer battery life, but it highly depends on the Venu-Display. The more often you use it, the more battery will be consumed.
That's a plus on the Fenix with it's always on display.

My wife does not miss a lot compared to my Fenix, it depends on your favorite activities

Thanks for your opinion and good to hear your wife doesn’t feel she is missing much. Does it take a while for hers to charge? 
even though I have an iPhone I don’t really want an Apple Watch. I want something a bit better in terms of tracking my fitness and apple doesn’t do a fantastic job. I do a lot of HIIT classes at F45 then do long walks and also some running. That’s about it really. I have considered the vivoactive 4s which would suit my smaller wrist I suppose but then again the nicer screen on the Venu is appealing but is it essential? I’m not so sure. Essentially they are exactly the same watch just one has a nicer screen. I guess I did like the fact the venu goes into a sleep mode unless you lift your wrist or touch it.  I would like to go for runs and walks without having to take my phone so hopefully they map things ok. Like I said I am so overwhelmed with choices and man Garmin have a lot of models and options 

The biggest reason to get a Fenix over the Venu is battery life. I don't know about you but I hate having to charge something other than my smartphone more than once a week. I previously had a Vivoactive 3 and always felt really insecure because I could not be sure if the battery lasted long enough or if the battery had gone down so much during the night that I had to charge it in the morning when I'm in a hurry. This made me not use VA3 24/7 and switch if off when not in use. I then bought Fenix 6 Pro and having owned it for a few weeks, I've only had to charge it once. At least for me, battery life means how comfortable I feel about wearing the watch all the time. 

Another reason to go for a Fenix might be looks/build quality. Don't get me wrong, the Venu looks nice but a Fenix looks more like an actual watch. Perhaps this isn't a concern for everyone but at these prices I'm looking for the watch to be suitable for every occasion from gym to a business meeting. The Fenix feels more substantial and serious whereas my old VA3 always felt like a plasticy toy around my wrist.

The Venu is more modern with its OLED touchscreen that makes the transflective screen of the Fenix look a bit old (although in sunlight a transflective screen is ways better). You might even get one of those (unfortunately common) Fenix screens with bluish tint when the backlight is on. However, with the backlight off (as it normally would be) and with its Always-On Display, a Fenix around the wrist will look more like a mechanical watch than a Venu with a non-AOD sreen that looks too 'HD' to mimic the watchface of a mechanical watch. As for touchscreens, I initially felt like it was a must but it's much easier to navigate my F6 Pro (buttons) than it was to navigate my VA3 (touchscreen) because the screen is so small that using the touchscreen can be inaccurate at times. Oh, and a touchscreen does not work when wet or if you wear gloves.

Oh Thankyou so so much I thought I was being a bit silly basing it just on battery life and the looks of it. I too hate having to charge things and I love a good quality watch. Do you find the Fenix quite thick and bulky? I measure my analogue watch at only 10mm thin so adding another 3.8 mm to it for the Fenix 6s means it’s going to sit up really high. Weight wise may be similar my analogue watch face is already 43g and with the metal stainless steel band it’s close to 50g anyway. I guess just the thickness of the Fenix 6s pro has me worried if it’s really going to cause a concern considering I’m female. I want to be able to sleep in it and not feel like I have something massive sticking up 

I was worried about the size and bulk initally as I'm a taller man with smaller hands. Years ago I tried out a Fenix 3 HR which put me off from Fenix watches because it felt so thich and heavy. However, as they made the current gen of Fenix watches lighter and thinner, I was surprised how 'low-profile' the F6 Pro felt on my wrist (felt much lighter and thinner than expected although it obviously still looks a bit thick). I am the type of person who would get bothered by an overly heavy/bulky watch but this is not the case with my Fenix.

As for sleeping with the watch on... There are people who cannot sleep with jewelry/watch on and obviously these people will get bothered by the Fenix. However, if you can sleep with a watch on, I doubt the current gen Fenix will offer a different experience.

Thanks for the feedback that certainly helps. No issue sleeping with watches

If this is your first sports watch - I'd actually recommend the Vivoactive.  It has a LOT of great features for the price.  Prices on the Vivoactive 3 here in the US have been truly dirt cheap.  If you can get it for a good price, you really couldn't go wrong with a Vivoactive 3, 4 or Venu... depending on if you really want the zippy display and features of the venu.  

And- as said above- these are less 'smart watches' than they are "sports" watches.  If you want a smart watch that tracks your runs and bike rides on the side- an AppleWatch may be a better choice.  Depends on your priorities.  

if battery life is really a necessity... you might want to look at the Coros watches.  

• Wow the 6x is big on her but def nicer looking. I’m glad to hear an honest opinion that she doesn’t feel like she’s missing out not having a Fenix 

Thanks for your honesty morey. Yes it is my first one and honestly it’s hard to know if I’ll fall in love with them or miss my old analogues. Hence why I was looking at a Va 4 of the Venu. I haven’t even thrown an Apple Watch into it even though I am an Apple fan with everything apple. I know they have terrible battery. I dislike their square shape. I know Garmin have better things for the fitness side of things

thanksnso much for everyone’s help I think I may just stick to the VA or Venu and see how I go, save some $$ and if I love it enough in a few years time jump up to something better. I imagine like all things technology they will only last a few years